Calibration of Beamforming Nodes in a Configurable Monitoring Device System

ABSTRACT

A system for radio frequency identification of a tag in an interrogation zone, includes a calibration node disposed in the interrogation zone to measure a signal strength of radio frequency identification signals from a beamforming system and provide signal data in accordance with the signal strength. A reader node is configured to receive the signal data and adjust the radio frequency identification signals generated by the beamforming system based upon the signal data. At least one of the calibration node, the reader node and the beamforming system is a configurable monitoring system. The calibration node, the reader node, and the beamforming system are coupled in a feedback control loop. The beamforming system includes a plurality of beamforming nodes. A signal of at least one beamforming node is optimized in accordance with the feedback control loop.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from provisional U.S. PatentApplication No. 61/248,140 filed Oct. 2, 2009 entitled “COMMUNICATIONSSYSTEMS AND METHODS USING CONFIGURABLE MONITORING DEVICES,” U.S. patentapplication Ser. No. 11/702,980 filed Feb. 5, 2007 entitled “SYSTEMS ANDMETHODS OF BEAMFORMING IN RADIO FREQUENCY IDENTIFICATION APPLICATIONS”issued as U.S. Pat. No. 7,652,577, U.S. patent application Ser. No.12/072,423 filed Feb. 25, 2008 entitled “LOCALIZING TAGGED ASSETS USINGMODULATED BACKSCATTER,” and U.S. patent application Ser. No. 12/636,564filed Dec. 11, 2009 entitled “SYSTEMS, METHODS AND APPARATUSES FORMANAGING CONFIGURABLE MONITORING DEVICES.”

TECHNOLOGICAL FIELD

Embodiments of the present invention relate generally to communicationsand systems management technology.

BACKGROUND

Conventional retail security systems, such as electronic articlesurveillance (EAS) systems, operate effectively to prevent shopliftingand the like. However, conventional systems are often limited to thenarrow scope of providing security functionality. For example, an EASgate located at an exit of a retail business establishment may beconfigured to alarm when an article with an EAS tag passes through thegate. Other than performing this important alarming functionality, manyconventional systems provide nothing more to the users of the systems,such as store owners, store managers, and the like. Additionally, whenstore owners are considering the purchase and installation of aconventional security system in a retail establishment, the limitedfunctionality offered by the systems can detrimentally affect thecost-benefit analysis of installing and maintaining the system.

BRIEF SUMMARY OF EXEMPLARY EMBODIMENTS

A system for radio frequency identification of a tag in an interrogationzone, includes a calibration node disposed in the interrogation zone tomeasure a signal strength of radio frequency identification signals froma beamforming system and provide signal data in accordance with thesignal strength. A reader node is configured to receive the signal dataand adjust the radio frequency identification signals generated by thebeamforming system based upon the signal data. At least one of thecalibration node, the reader node and the beamforming system is aconfigurable monitoring system. The calibration node, the reader node,and the beamforming system are coupled in a feedback control loop. Thebeamforming system includes a plurality of beamforming nodes. A signalof at least one beamforming node is optimized in accordance with thefeedback control loop. A signal to noise ratio of at least onebeamforming node is optimized in accordance with the feedback controlloop. A phase of at least one beamforming node is optimized inaccordance with the feedback control loop. The plurality of beamformingnodes form a one dimensional beamforming array or a two dimensionalarray.

A plurality of tags is arranged in a mesh with tag to tag communicationbetween at least two of the tags in the mesh. A tag within theinterrogation zone is localized in accordance with range data based onthe tag to tag communication. A tag within the interrogation zone islocalized in accordance with a combination of the signal data and rangedata based on the tag to tag communication. A tag within theinterrogation zone is localized in accordance with the signal data and abeacon signal provided within the interrogation zone. The beacon signalhas multiple ranges for providing multiple range determinations tolocalize the tag by performing a logical operation on the multiple rangedeterminations. The beacon signal is provided by a configurablemonitoring device configured as a beacon. The signal data is transmittedto the reader node by way of the tag to tag communication. The signaldata is transmitted to the reader node by way of network activity nodes.The signal data is transmitted to the reader node by way of a gatewaynode. The beamformer system receives the signal data and adjusts theradio frequency identification signals based on the signal data. Thebeamformer system receives the signal data by way of a control radiofrequency connection. The beamformer system receives the signal data byway of a hardwired connection.

In a tag communication system, a method includes determining rangeinformation representative of a distance between two tags of a pluralityof tags, and estimating parameter information representative ofbackscatter signals of a marker tag and an asset tag. A tag of theplurality of tags is localized in accordance with the range informationand the parameter information to provide a localized tag. The rangeinformation is determined in accordance with a beacon signal. The systemincludes a plurality of beacon signals and the method further includesdetermining the range information in accordance with at least two beaconsignals of the plurality of beacon signals. A logical operation isperformed on the range information of the at least two beacon signals. Afurther beacon signal has a plurality of signal ranges and the rangeinformation is determined in accordance with the plurality of signalranges. A logical operation is performed on the range information of theplurality of signal ranges. The parameter information includes antennaarray response information, angle information, time of flightinformation, signal strength information or signal to noise information.

An electromagnetic signal is scanned across a zone including thelocalized tag using a transmit beamforming array. The scanning isperformed using a receive beamforming array with a plurality of antennasconfigured to receive the modulated backscatter signal from thelocalized tag. At least one of the localized tag and the beamformingarray is a configurable monitoring device. The range information and theparameter information are represented by backscatter signals from twodifferent sources of electromagnetic signals. The tag communicationsystem includes an information gathering node and the range informationis communicated to the information gathering node. The range informationis communicated to the information gathering node by way of a gatewaynode.

A plurality of tags is arranged in a mesh and the range information iscommunicated to the information gathering node by way of the mesh. Themesh includes at least two tags with tag to tag communication and therange information is communicated to the information gathering node byway of the tag to tag communication within the mesh. The rangeinformation is communicated to the information gathering node by way ofa network activity node. The beacon signal is provided by a configurablemonitoring device configured as a beacon. The estimating is performed inaccordance with a configurable monitoring device configured as acalibration node in a beamforming feedback loop.

Some example embodiments of the present invention are therefore providedthat support security system functionality, as well as, additionalfunctionalities that would be beneficial to store owners, storemanagers, and customers. For example, some example embodiments supportinventory and marketing functionality, as well as, advanced securityfunctionality.

According to some example embodiments, a system is provided for managingconfigurable monitoring devices. A configurable monitoring device may bea microprocessor-based wireless communication device that can assumeconfigurable roles or modes of operation within the system. A mode ofoperation may be implemented based on configuration information storedon the configurable monitoring device. The configuration information maybe pre-loaded on the configurable monitoring device, or configurablemonitoring devices may receive the configuration information via awireless connection to a network.

The system, referred to as a monitoring system, may include any numberof configurable monitoring devices configured to operate, for example,as a mesh network. Regardless of whether a network in accordance withexample embodiments of the present invention is a mesh network, anetwork may include a gateway node that supports a monitoring terminal(also referred to as a coordinator). The gateway node may operate as aninterface between the configurable monitoring device network and themonitoring terminal, for example, via an external network. Themonitoring terminal may be configured to interact with the configurablemonitoring devices and the configurable monitoring device network toimplement a variety of functionalities.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

The invention will be described in conjunction with the followingdrawings in which like reference numerals designate like elements andwherein:

FIG. 1 is a schematic block diagram of a monitoring system including anumber of configurable monitoring devices according to an exampleembodiment of the present invention;

FIG. 1A is a block diagram showing various function components of aconfigurable monitoring device (CMD) according to an exemplaryembodiment of the present invention;

FIG. 1B is a block diagram of various physical components of the CMDaccording to an exemplary embodiment of the present invention;

FIG. 1C illustrates is a flow diagram illustrating the configuration ofa CMD according to an exemplary embodiment;

FIG. 2 illustrates a block diagram of a monitoring terminal according toan example embodiment;

FIG. 3 illustrates a diagram of various configurable monitoring devicesimplemented in an example retail environment in accordance with anexample embodiment of the present invention;

FIG. 4 illustrates an example of a flow diagram illustrating an examplemethod for managing configurable monitoring devices according to anexample embodiment;

FIGS. 5A,B illustrate an example user interface window implemented by amonitoring terminal and depicting a representation of a monitoringsystem according to an example embodiment;

FIG. 6 illustrates a tag information window for displaying attributeinformation for a tag according to an example embodiment;

FIG. 7 illustrates a hub information window for displaying attributeinformation for a node according to an example embodiment;

FIG. 8 illustrates a tag battery level window for displaying the batterylevel for a tag according to an example embodiment;

FIG. 9 illustrates a flow chart of an example tag according to anexample embodiment;

FIG. 10 illustrates an example configurable monitoring device withspecialized hardware for performing some of the functionality within therole of a node according to an example embodiment;

FIG. 11 illustrates an example configurable monitoring device withspecialized hardware for performing some of the functionality within therole of a key according to an example embodiment;

FIG. 12 illustrates a signaling diagram for an association procedureaccording to an example embodiment;

FIG. 13 illustrates a signaling diagram for an dissociation procedureaccording to an example embodiment;

FIG. 14 illustrates a beamforming system for a radio frequencyidentification application, according to various embodiments of thepresent invention.

FIG. 15 is a block diagram of a beamforming system for a radio frequencyidentification application, according to various embodiments of thepresent invention.

FIG. 16 is a block diagram of a reader node, according to variousembodiments of the present invention.

FIG. 17 is a block diagram of a beamforming control system, according tovarious embodiments of the present invention.

FIG. 18 is a block diagram of a beamforming node system, according tovarious embodiments of the present invention.

FIG. 19 is a block diagram of a calibration node system, according tovarious embodiments of the present invention.

FIG. 20 illustrates a beamforming array, according to variousembodiments of the present invention.

FIG. 21 illustrates methods of beamforming, according to variousembodiments of the present invention.

FIG. 22 illustrates methods of reading data from RFID tags, according tovarious embodiments of the present invention.

FIG. 23 illustrates methods of beamforming, according to variousembodiments of the present invention.

FIG. 24 illustrates a localizing system using marker tags and assettags.

FIG. 25 illustrates a localizing system in a shelf application.

FIG. 26 illustrates a localizing system in a dock door application.

FIG. 27 is a block diagram of an exemplary transmitter beamformingsystem.

FIG. 28 is a block diagram of an exemplary receiver beamforming system.

FIG. 29 illustrates a localizing system in a multipath environment.

FIG. 30 illustrates a localizing system in a two-dimensional mobilereader configuration.

FIGS. 31A-D illustrate embodiments of configurable monitoring systemssuitable for beamforming and localization of devices in tagcommunication systems.

FIG. 32 illustrates an embodiment of the configurable monitoring systemof the invention.

DETAILED DESCRIPTION

The following disclosure is an improvement on the following U.S. utilityapplications or provisional applications, namely, U.S. Application Ser.Nos. 61/244,320 filed Sep. 21, 2009 and 61/246,388 filed Sep. 28, 2009both entitled “A CONFIGURABLE MONITORING DEVICE;” U.S. Application Ser.No. 61/246,393 filed Sep. 28, 2009 entitled “SYSTEMS, METHODS ANDAPPARATUSES FOR MANAGING CONFIGURABLE MONITORING DEVICES;” U.S.Application Ser. No. 61/246,393 filed Sep. 28, 2009 entitled “SYSTEMS,METHODS AND APPARATUSES FOR MANAGING CONFIGURABLE MONITORING DEVICES;”U.S. Application Ser. No. 60/765,331 filed Feb. 4, 2006 titled “METHODSAND ARCHITECTURES FOR INCREASING RANGE AND RELIABILITY IN RFID SYSTEMS;”Ser. No. 11/702,980 filed Feb. 5, 2007, entitled “SYSTEMS AND METHODS OFBEAMFORMING IN RADIO FREQUENCY IDENTIFICATION APPLICATIONS;” Ser. No.12/072,423 filed Feb. 25, 2008 titled “LOCALIZING TAGGED ASSETS USINGMODULATED BACKSCATTER;” 61/070,024 filed Mar. 20, 2008 titled“FUNCTIONALITY ENHANCEMENT IN RADIO FREQUENCY IDENTIFICATION SYSTEMS;”Ser. No. 12/407,383 filed Mar. 19, 2009 titled “APPLIQUE NODES FORPERFORMANCE AND FUNCTIONALITY ENHANCEMENT IN RADIO FREQUENCYIDENTIFICATION SYSTEMS;” 61/069,812 filed Mar. 19, 2008 and Ser. No.12/406,629 filed Mar. 18, 2009 both titled “RANGE EXTENSION AND MULTIPLEACCESS IN MODULATED BACKSCATTER SYSTEMS,” 61/190,791 filed Sep. 3, 2008and Ser. No. 12/548,993 filed Aug. 27, 2009 both titled “RFID REPEATERFOR RANGE EXTENSION IN MODULATED BACKSCATTER SYSTEMS;” and 61/159,305filed Mar. 11, 2009 titled “LOCALIZATION USING VIRTUAL ANTENNA ARRAYS INMODULATED BACKSCATTER RADIO FREQUENCY IDENTIFICATION SYSTEMS.”

All of these entire disclosures are incorporated by reference herein.

Some embodiments of the present invention will now be described morefully hereinafter with reference to the accompanying drawings, in whichsome, but not all embodiments of the invention are shown. Indeed,various embodiments of the invention may be embodied in many differentforms and should not be construed as limited to the embodiments setforth herein; rather, these embodiments are provided so that thisdisclosure will satisfy applicable legal requirements Like referencenumerals refer to like elements throughout.

As defined herein a “computer-readable storage medium,” which refers toa physical storage medium (e.g., volatile or non-volatile memorydevice), can be differentiated from a “computer-readable transmissionmedium,” which refers to an electromagnetic signal. Additionally, asused herein, the term “circuitry” refers to not only hardware-onlycircuit implementations including analog and/or digital circuitry, butat least also to combinations of circuits with corresponding softwareand/or instructions stored on a computer-readable storage medium.

As indicated above, example embodiments of the present invention may beconfigured to support various security, inventory, marketing, and otherfunctionalities in, for example, a retail sales environment. To do so,configurable monitoring devices may be installed within the retail salesenvironment. A description of some example embodiments of configurablemonitoring devices, and the monitoring systems that may supportconfigurable monitoring devices, is provided in U.S. Provisional PatentApplication 61/244,320 filed Sep. 21, 2009, entitled “A ConfigurableMonitoring Device”, the content of which is hereby incorporated byreference in its entirety. The configurable monitoring devices may bewireless communication devices that can be dynamically configured toassume one or more roles within the operation of a monitoring system. Tofacilitate the ability to dynamically change roles, the configurablemonitoring devices may include a processor, memory, communicationsinterface (e.g., radio transmitter/receiver, Radio Frequency ID (RFID)module, or the like). Based on a role that a configurable monitoringdevice is expected to assume, the configurable monitoring device mayalso include more specialized hardware components such as, an alarm, asensor, a display, and the like.

As indicated above, the configurable monitoring devices may assume avariety of roles within the monitoring system. For example, aconfigurable monitoring device may be configured as a security tag thatis affixed to an article via a mounting device. The security tag may beconfigured to alarm or transmit an alarm message, if the security tagdetermines that an alarm condition has been met. In another example, aconfigurable monitoring device may be configured to operate as a nodewithin a monitoring system. As a node, the configurable monitoringdevice may support communications and message routing within thecommunications network defined by the system. In this regard, the nodemay be configured to determine routing paths within the network for theefficient delivery of messages. According to another example, aconfigurable monitoring device may be configured to operate as a gatewaybetween the monitoring system and an external network such as a wiredlocal area network (LAN) or the Internet. Further, a configurablemonitoring device may be configured to operate as a security key forlocking and unlocking a mounting device associated with a security tag.In this regard, the security key may be configured to activate ordeactivate electronic security features of a security tag. For purposesof explanation, a configurable monitoring device configured to operatein node mode will be referred to as a “node”, a configurable monitoringdevice configured to operate in tag mode will be referred to as a “tag”,a configurable monitoring device configured to operate in gateway modewill be referred to as a “gateway”, and a configurable monitoring deviceconfigured to operate in key mode will be referred to as a “key”.

The roles of the configurable monitoring devices described above, andfurther described below is not an exhaustive list of the roles that maybe implemented by the configurable monitoring devices. Additionally,while the various roles may be described separately, it is contemplatedthat a single configurable monitoring device may be configured tosimultaneously assume more than one of the roles.

FIG. 1 illustrates an example monitoring system 60 that includes anumber of configurable monitoring devices in various roles. Tags 68(e.g., tags 68 a-68 i) may be configurable monitoring devices affixed toa product for the purpose of supporting security, inventory, marketing,as well as other functionalities. Network activity nodes 66 (e.g., nodes66 a-66 c) may be configured to support network level activities such ascommunications routing, tag locating, and the like.

Gateway node 64 may be configured as a gateway node to provide a networkinterface between the monitoring system 60 and the external network 30.A monitoring terminal 62 may be in communication with the gateway node64, for example, via the external network 30 or via a direct connectionto the gateway node 64, to facilitate management of the configurablemonitoring devices by the monitoring terminal 62 and to furtherfacilitate the aggregation and analysis of data received from theconfigurable monitoring devices. A gateway node may interface with acellular network to gain access to other networks, such as the Internet.In some example embodiments, a gateway node may support USB and Ethernetconnectivity for connection to USB or Ethernet networks.

The gateway node 64 may also include or be associated with a networkcoordinator. The network coordinator may be configured to oversee andmanage various network operations. For example, the network coordinatormay implement the forming of the network, allocate network addresses toentities of the network, and maintain a binding table for the network.

In some cases, the monitoring system 60 may be made up of a plurality ofcommunication devices (e.g., such as a plurality of configurablemonitoring devices) in communication with each other viadevice-to-device communication to form a mesh network. However, in othersituations, the network may include a plurality of devices that transmitsignals to and receive signals from a base site or access point, whichcould be, for example a base site or access point of a data network,such as a local area network (LAN), a metropolitan area network (MAN),and/or a wide area network (WAN), such as the Internet.

Other devices such as processing elements or devices (e.g., personalcomputers, server computers, displays, point of sale (POS) terminalsand/or the like) may be coupled to a configurable monitoring device toaccess the monitoring system 60. By directly or indirectly connectingthe configurable monitoring devices to various network devices and/or toother configurable monitoring devices via the monitoring system 60, theconfigurable monitoring devices may be enabled to receive configurationmodifications dynamically and perform various functions or tasks inconnection with network devices or other configurable monitoring devicesbased on the current configuration of the configurable monitoringdevices.

The configurable monitoring devices, and the monitoring system 60generally, may utilize any wireless communication technique forcommunicating information between the devices or to the monitoringterminal 62. For example, the configurable monitoring devices may beconfigured to support communications protocols built on the IEEE802.15.4 standard, such as Zigbee or a proprietary wireless protocol.According to some example embodiments, the communications within themonitoring system 60 may be performed based on a Route Under MAC (MediaAccess Control) (RUM) protocol or a modified RUM protocol. Regardless ofthe protocol, communications within the monitoring system may beassociated with a network identifier, such as a personal area network(PAN) identifier. In some example embodiments, configurable monitoringdevices might not be permitted to communicate within the monitoringsystem without having a matching network identifier. In some exampleembodiments, the monitoring system may regularly or irregularly changethe network identifier and transition to a new network identifier forsecurity purposes.

Additionally, to support network communications within the monitoringsystem, a system-wide synchronized clock may be implemented.Synchronization of the clock may be maintained via a clock signal.Configurable monitoring devices may include real time clock circuitry tosupport the synchronized clock and to regulate the use of precisecommunications windows.

The configurable monitoring devices may also support RFIDcommunications, such as communications based on Generation II Ultra HighFrequency (UHF) RFID standards. In example embodiments where aconfigurable monitoring device includes a radio (e.g., an IEEE 802.15.4radio) and an RFID module, the configurable monitoring device may beconfigured to operate as an interface that allows RFID devices to accessthe monitoring system 60. For example, an RFID reader or other RFIDdevice, that does not include a configurable monitoring device, maycommunicate with a configurable monitoring device, such as a tag, andthe configurable monitoring device may relay such communications toentities connected to the monitoring system. In the same manner, the tagmay relay communications originating on the monitoring system to an RFIDdevice that has interfaced with a tag. As such, the configurablemonitoring devices may operate as gateway to the monitoring system forRFID communications.

The monitoring system 60 may be configured to operate as a mesh networkor a hybrid mesh network. In some example embodiments, the monitoringsystem is configured in a star network structure, a hybrid star networkstructure, a cluster tree or the like. In this regard, the monitoringsystem 60 may support message hopping and network self-healing. Withrespect to message hopping, the nodes 66 may be configured to receivecommunications from nearby or assigned tags 68. The nodes 66 may beconfigured to determine a system architecture and/or efficient pathwaysfor communicating messages to the various entities within the network.In this regard, the nodes 66 may be configured to generate and maintainrouting tables to facilitate the efficient communication of informationwithin the network. A block diagram of an example node device inaccordance with various example embodiments is depicted in FIG. 10. Theexample node of FIG. 10 supports both star and mesh networks byincluding star and mesh network routers. The example node of FIG. 10 isalso depicted as being configured to communicate using Zigbee, as wellas RFID protocols.

For example, in accordance with implemented marketing functionality, tag68 h may be configured to communicate that the product that tag 68 h isaffixed to has been moved from its display location. Tag 68 h may beconfigured to communicate this information to tags 68 g and 68 d,because the products affixed to tags 68 g and 68 d are related productsthat a customer may be interested in purchasing, given the customer'sapparent decision to purchase the product affixed to tag 68 h.Accordingly, tag 68 h may generate and transmit a message addressed totags 68 g and 68 d. The message may be received by node 66 c, and node66 c may be configured to determine how to route the message, givencurrent network traffic, such that the message is efficiently receivedby tags 68 g and 68 d. For example, using generated routing tables, node66 c may determine that the message can first be transmitted directly totag 68 g, since tag 68 g is connected to or in direct communication withthe node 66 c. To transmit the message to tag 68 d, node 66 c maydetermine that the message should be forwarded to node 66 b. Node 66 bmay perform a similar analysis and determine that the message can beforward to tag 68 d, directly from node 66 b. Tag 68 h may also beconfigured to transmit the message to the monitoring terminal 62. Node66 c may route the message accordingly, such that the gateway 64 mayforward the message to the monitoring terminal 62.

As indicated above, the nodes 66 may be configured to performcommunications routing within the monitoring system 60. In this regard,nodes 66 may operate to extend the range of the monitoring system.However, according to some example embodiments, all configurablemonitoring devices within the monitoring system 60 may be configured toperform routing functionality. As such, configurable monitoring devicesconfigured to operate both as tags and as nodes may communicate directlywith each other, if within range, without having to route thecommunications through another node.

Further, since the monitoring system 60 may be configured as a mesh orhybrid mesh network, the monitoring systems 60 may support self-healing.In this regard, in the event that a node 66 should fail and no longer beable to communicate, messages may be automatically routed via a paththat does not involve the failed node. For example, in a given scenario,a tag may be connected to more than one node. In the event that one ofthe nodes fails, the tag may simply cause messages to be routed throughanother node to which the tag is connected. According to some exampleembodiments, for example in the event that another available node is notpresent, a tag may be triggered, directed, or configured to implementnode functionality (e.g., stored in the memory of the tag andimplemented by a processor of the tag). The tag may therefore become anode to support communications of other tags.

According to some example embodiments, configurable monitoring devicesthat are installed and configured with the intention that the devices beprimarily utilized as nodes may be powered through a building's wiredpower system or be mains powered (in contrast to being only batterypowered). Since nodes may be involved in the frequent transmission ofcommunications, power utilization of a node may be relatively high. Assuch, since configurable monitoring devices configured to operateprimarily as tags would likely be battery powered for mobility purposes,an example embodiment that implements node functionality within a tagmay be a temporary solution to maintain network continuity while thefailed node is repaired.

Additionally, the monitoring system 60 may be configured to compensatefor interference and multi-path conditions that can arise in enclosedenvironments, such as retail stores. To do so, the monitoring system 60may be configured, for example by the monitoring terminal 62, to modifythe signal power of select nodes and tags to minimize interference.According to some example embodiments, directional antennas may also beused by configurable monitoring devices to minimize interference.

According to various example embodiments, the monitoring system 60 maybe configured to interface with any number of other types of networksand/or systems. For example, the monitoring system 60 may interface withEAS systems, RFID systems, closed circuit television systems, inventorysystems, security systems, sales systems, shipping systems, point ofsale terminals, advertising systems, marketing compliance systems,ordering systems, restocking systems, virtual deactivation systems,Lojack® systems, and the like.

While the monitoring system 60 may be configured to operate in adistributed fashion, the monitoring terminal 62 may be configured tocoordinate operations of the monitoring system 60, as well as, retrieve,aggregate, and analyze data provided by the configurable monitoringdevices of the system.

Based on the foregoing, and in accordance with some example embodiments,the nodes may be configured to provide a wireless signal that may bereceived by tags that are within range. According to some exampleembodiments, the range of a node or the power of the signal provided bythe node may be set based on the size of the area that the node isresponsible for. For example, if the node is associated with a smallfloor display, the signal power may be relatively low. On the otherhand, if a node is responsible for a large shelf unit, the signal powermay be set to a higher level to ensure coverage of the entire shelfunit.

Tags may be configured to receive a signal that is associated with anode and respond to the node indicating that the tag is now associatedwith the node, for example, because the tag is located on the floordisplay associated with the node. For example, a tag may be configuredto periodically or pseudo-randomly power up (e.g., based on a wake-uptimer), listen for a node signal (e.g., a beacon signal), perform a timesynchronization based on the nodes signal, and transmit a messageindicating which node the tag has received a signal from. Subsequently,a tag may perform a second clock synchronization and then power downinto a sleep mode for another period of time. From the signal providedby the node, the tag may receive a unique identifier for a node that thetag has detected and may store the identifier. As such, the tag wouldknow to which node the tag has been associated. Similarly, the node mayreceive a communication from a tag including a unique identifier of thetag, and the node may therefore know to which tags the node isassociated, and the node may be configured to report the node/tagassociations back to a monitoring terminal, or monitoring systemcoordinator. Via these and other types of defined tag/noderelationships, various functionalities, as mentioned above and otherwiseherein, may be implemented.

Additionally, as further described herein, a tag may include a jiggleswitch, the actuation of which may indicate that a tag is being moved.Upon detecting actuation of the jiggle switch, a tag may move from asleep state into an awake state. Upon entering the awake state, the tagmay perform one or more clock synchronizations with a node and determinethe identifier of the node to which the tag is currently connected, andtransmit a message indicating the identifier of the node to which thetag is currently connected (possibly a new node since movement may haveoccurred). In the event that a tag does not detect a node, the tag mayalarm. A tag that has detected a node may implement a movement waittimer to facilitate determining whether further movement of the tag isoccurring. In the event that further movement is detected during themovement wait time, the tag may again perform a time synchronization anddetect a node. If the movement wait time expires, the tag may determinea time until a next wake up into the awake state and an associatedwake-up timer may be reset. Upon beginning the wake-up timer the tag maytransfer into a sleep state. FIG. 9 illustrates a flow chart of theoperation of an example tag as described above.

FIGS. 1A and 1B illustrate basic block diagrams of a configurablemonitoring device 10 according to an exemplary embodiment. As shown inFIGS. 1A and 1B, the configurable monitoring device 10 may includevarious components that support both basic operation of the configurablemonitoring device 10 and operation of the configurable monitoring device10 in any of its various configurable roles and/or modes. Some examplesof these components are shown in FIGS. 1 and 2. However, it should beappreciated that some embodiments may include either more or less thanthe example components illustrated in FIGS. 1A and 1B. Thus, theembodiments of FIGS. 1A and 1B are provided by way of example and not oflimitation.

FIG. 1A is a block diagram showing various functional components of theconfigurable monitoring device 10 according to an exemplary embodiment.FIG. 1B is a block diagram of various physical components of theconfigurable monitoring device 10 according to an exemplary embodiment.Reference will now be made to both FIGS. 1A and 1B in order to describean example structure and functional operation of the configurablemonitoring device 10 according to an exemplary embodiment. In thisregard, as shown in FIG. 1A, the configurable monitoring device 10 mayinclude a processor 20 and a communication interface 22. In some exampleembodiments, the processor 20 may be part of a Linux single boardcomputer (SBC) and configured to support and execute a Structured QueryLanguage (SQL) server. The processor 20 may in turn communicate with,control or embody (e.g., via operation in accordance with correspondinginstructions) a configuration manager 24 and an alarm module 26.Meanwhile, as shown in FIG. 2, the configurable monitoring device 10 mayinclude such physical components as the processor 20, a battery 40, analarm 42, a memory device 44, a radio transmitter/receiver 46, and anRFID module 48. In some cases, the configurable monitoring device 10 mayfurther include a sensor 50 and a mounting device 52.

In an exemplary embodiment, the processor 20 may be configured (e.g.,via execution of stored instructions or operation in accordance withprogrammed instructions) to control the operation of the configurablemonitoring device 10. The processor 20 may be embodied in a number ofdifferent ways. For example, the processor 20 may be embodied as one ormore of various processing means or devices such as a coprocessor, amicroprocessor, a controller, a digital signal processor (DSP), aprocessing element with or without an accompanying DSP, or various otherprocessing devices including integrated circuits such as, for example,an ASIC (application specific integrated circuit), an FPGA (fieldprogrammable gate array), a microcontroller unit (MCU), a hardwareaccelerator, a special-purpose computer chip, or the like. In anexemplary embodiment, the processor 20 may be configured to executeinstructions stored in a memory device (e.g., memory device 44 of FIG.2) or otherwise accessible to the processor 20. The instructions may bepermanent (e.g., firmware) or modifiable (e.g., software) instructions.Alternatively or additionally, the processor 20 may be configured toexecute hard coded functionality. As such, whether configured byhardware or software methods, or by a combination thereof, the processor20 may represent an entity (e.g., physically embodied in circuitry)capable of performing operations according to embodiments of the presentinvention while configured accordingly. Thus, for example, when theprocessor 20 is embodied as an ASIC, FPGA or the like, the processor 20may be specifically configured hardware for conducting the operationsdescribed herein. Alternatively, as another example, when the processor20 is embodied as an executor of software or firmware instructions, theinstructions may specifically configure the processor 20 to perform thealgorithms and/or operations described herein when the instructions areexecuted. The processor 20 may include, among other things, a clock, anarithmetic logic unit (ALU) and logic gates configured to supportoperation of the processor 20.

The processor 20 may also include input/output (I/O) ports (or pins).Via configuration information, the I/O ports may be configured tointerface with any number of external devices such as, electronicsecurity devices, alarms, speakers, piezo buzzer, microphones, lights(e.g., light emitting diodes (LEDs) including dual-color LEDs), buttons,keypads, monitors, displays (e.g., for changeable pricing labels),sensors (e.g., accelerometers, movement sensors (e.g., jiggle switch),light sensors, temperature sensors, cameras, security gates, store audiosystems, customer counters, lighting switches, employee communicators(e.g., headsets, handheld radios), door strike mats, jewelry case mats,Lojack® devices, global positioning system (GPS) devices, barcodescanners, loyalty card scanners, and the like. As such, the I/O portsmay be configured to support one or more roles that the configurablemonitoring device may be configured to perform. For example, an I/O portthat is configured to interface with a light sensor may be used todetermine whether a protected article has been placed under a coat orotherwise concealed. As another example, an I\O port may interface withan LED to cause the LED to flash at a regular interval to provide avisual indication of the status of the configurable monitoring deviceand a deterrent to would-be thieves. For yet another example, an I\Oport may be configured to interface with a piezo buzzer to play varioustones by the processor 20. According to various example embodiments,actuation of the jiggle switch and detection of the actuation by the I/Oports may be a trigger for the configurable monitoring device totransition from a sleep state to an awake state.

Via the I/O ports of the processor 20, various functionalities may betriggered, based on the role and the configuration information of theconfigurable monitoring device. Triggering may be initiated either atthe configurable monitoring device level or at the system or monitoringterminal level. For example, the I/O ports of a configurable monitoringdevice's processor may interface with a display for a price tag, wherethe configurable monitoring device is configured as a tag. Within thetag's configured role, for example, the price depicted on the displaymay be set to reduce at a given time. In some example embodiments, thetime may monitored by the processor of the tag and when the given timeis reached, the processor may direct the I/O ports and the connecteddisplay to depict a reduced price. Alternatively, an example thatincludes triggering at the monitoring terminal level may include thetime being monitored by the monitoring terminal, and the monitoringterminal may communicate a message including a reduced price, or anindication to reduce the price, to the tag at the given time to triggerthe tag to reduce the price accordingly.

The memory device 44 may include, for example, one or more volatileand/or non-volatile memories. In other words, for example, the memorydevice 44 may be an electronic storage device (e.g., a computer-readablestorage medium) comprising gates configured to store data (e.g., bits)that may be retrievable by a machine (e.g., a computing device includinga processor such as processor 20). The memory device 44 may beconfigured to store information, data, applications, instructions or thelike for enabling the configurable monitoring device 10 to carry outvarious functions in accordance with exemplary embodiments of thepresent invention. For example, the memory device 44 could be configuredto buffer input data for processing by the processor 20. Additionally oralternatively, the memory device 44 could be configured to storeinstructions for execution by the processor 20.

In some environments, the communication interface 22 may alternativelyor also support wired communication. For example, in some exampleembodiments, such as when the configurable monitoring device isconfigured to operate as a POS (point of sale) node, the communicationsinterface may support wired communication via an RJ45 port. As such, forexample, the communication interface 22 may include a communicationmodem and/or other hardware/software for supporting communication viacable, digital subscriber line (DSL), universal serial bus (USB) orother mechanisms.

In an exemplary embodiment, the communication interface 22 may supportcommunication via one or more different communication protocols ormethods. In some embodiments, the communication interface 22 may beconfigured to support relatively low power, low data rate communication.As such, for example, a low power and short range communication radio(e.g., radio transmitter/receiver 46) may be included in thecommunication interface 22. In some examples, the radiotransmitter/receiver 46 may include a transmitter and correspondingreceiver configured to support radio frequency (RF) communication inaccordance with an IEEE (Institute of Electrical and ElectronicsEngineers) communication standard such as IEEE 802.15. As such, forexample, some embodiments may employ Bluetooth, Wibree, ultra-wideband(UWB), WirelessHART, MiWi or other communication standards employingrelatively short range wireless communication in a network such as awireless personal area network (WPAN). In some cases, IEEE 802.15.4based communication techniques such as ZigBee or other low power, shortrange communication protocols such as a proprietary technique based onIEEE 802.15.4 may be employed. According to some example embodiments,the communications interface 22 may be configured to support an InternetProtocol version 6 (IPV6) stack.

The communications interface 22 may also support a Route Under MAC(Media Access Control) (RUM) protocol or a modified RUM protocol.Regardless of the protocol, the communications interface 22 may beconfigured to utilize a network identifier, for example stored in thememory device 44, such as a personal area network (PAN) identifier. Insome example embodiments, a configurable monitoring device might not bepermitted to communicate within the monitoring system without using amatching network identifier.

According to some example embodiments, a configurable monitoring device,or the monitoring system, may select a communications channel for usewith monitoring system communications to implement a fixed channelscheme. A monitoring device may, based on the noise or channel traffic,select a quiet channel. However, a procedure may be implemented by themonitoring terminal and the configurable monitoring devices thatprovides for changing channels, for example, when a channel begins tooperate poorly. According to some example embodiments, the monitoringterminal may communicate to the nodes to change channels, but the tagsmay perform a channel scan to determine the new channel.

In example embodiments where a configurable monitoring device 10includes a radio transmitter/receiver 46 (e.g., an IEEE 802.15.4 radio)and an RFID module 48, the configurable monitoring device may beconfigured to operate as an interface that allows RFID devices to accessa monitoring system. For example, an RFID reader or other RFID device,that does not include a configurable monitoring device, may communicatewith a configurable monitoring device, such as a tag, and theconfigurable monitoring device may relay the communications to entitiesconnected to the monitoring system. In the same manner, the tag mayrelay communications initiated on the monitoring system to an RFIDdevice that has interfaced with a tag. As such, the configurablemonitoring devices may operate as a gateway to the monitoring system forRFID communications.

The network 30 to which the communication interface 22 may connect(which may include the monitoring system) may be a local network (e.g.,a WPAN) that may in some cases further connect to or otherwisecommunicate with a remote network on either a periodic or continuousbasis. For example, via the communications interface 22, a configurablemonitoring device may interface with EAS systems, RFID systems, closedcircuit television systems, inventory systems, security systems, salessystems, shipping systems, point of sale terminals, advertising systems,marketing compliance systems, ordering systems, restocking systems,virtual deactivation systems, Lojack® systems, and the like.

The network 30 may include a collection of various different nodes,devices or functions that may be in communication with each other viacorresponding wired and/or wireless interfaces. As such, theillustration of FIG. 1A should be understood to be an example of a broadview of the network and not an all inclusive or detailed view of thenetwork 30. In some cases, the network 30 may be made up of a pluralityof communication terminals (e.g., such as a plurality of configurablemonitoring devices) in communication with each other viadevice-to-device communication to form a mesh network. However, in othersituations, the network may include a plurality of devices that eachinclude an antenna or antennas for transmitting signals to and forreceiving signals from a base site or access point, which could be, forexample a base site or access point of a data network, such as a localarea network (LAN), a metropolitan area network (MAN), and/or a widearea network (WAN), such as the Internet. In turn, other devices such asprocessing elements or devices (e.g., personal computers, servercomputers, displays, point of sale (POS) terminals and/or the like) maybe coupled to the configurable monitoring device 10 via the network 30.By directly or indirectly connecting the configurable monitoring device10 to various network devices and/or to other configurable monitoringdevices via the network 30, the configurable monitoring device 10 may beenabled to receive configuration modifications dynamically and performvarious functions or tasks in connection with network devices or otherconfigurable monitoring devices based on the current configuration ofthe configurable monitoring device 10.

As indicated above, the processor 20 of an exemplary embodiment may beembodied as, include or otherwise control the configuration manager 24and/or the alarm module 26. The configuration manager 24 and the alarmmodule 26 may each be any means such as a device or circuitry operatingin accordance with firmware/software or otherwise embodied in hardwareor a combination of hardware and firmware/software (e.g., processor 20operating under software control, the processor 20 embodied as an ASICor FPGA specifically configured to perform the operations describedherein, or a combination thereof) thereby configuring the device orcircuitry to perform the corresponding functions of the configurationmanager 24 and/or the alarm module 26, respectively, as describedherein. Thus, in examples in which software is employed, a device orcircuitry (e.g., the processor 20 in one example) executing the softwareforms the structure associated with such means.

The configuration manager 24 may be configured to control operation ofthe configurable monitoring device 10 based on configuration informationprovided to the configurable monitoring device 10 (e.g., via thecommunication interface 22) or pre-stored in the configurable monitoringdevice 10. According to some example embodiments, the configurationmanager 24, with the communications interface, may support a wirelessbootloading. As such, for example, the configuration manager 24 may beconfigured to determine and/or control the configuration and therebyalso the operation of the configurable monitoring device 10 based on thecurrent situation as determined by the configuration manager 24 or basedon the instructions received by the configuration manager 24.

Roles or configurations may be simple or complex based on, for example,the processing capabilities of the processor 20 and the memory storageof the memory device 44. In this regard, a configurable monitoringdevice may be configured to perform minimal data processing, and amonitoring terminal that coordinates and manages a monitoring system maybe configured to perform incrementally more processing of data.Alternatively, some configurable monitoring devices may includerelatively higher processing power and larger memory storage to supportincreased data processing at the configurable monitoring device, ratherthan at the monitoring terminal.

For example, in embodiments where a configurable monitoring device,configured as a tag, includes minimal storage memory, attributeinformation describing an article to which the tag is affixed may bestored at the monitoring terminal. When an inquiry device (e.g., pricescanner, inventory scanner) requests the attribute information from thetag, the tag may communicate the request to the monitoring terminal, andthe monitoring terminal may provide the attribute information to theinquiry device, either through the monitoring system or through aconnection external to the monitoring system.

Alternatively, in embodiments where memory device 44 includes arelatively large storage memory, attribute information describing thearticle to which a tag is affixed may be stored local to the tag, withinthe memory device 44. When an inquiry device (e.g., price scanner,inventory scanner) requests the attribute information from the tag, thetag may directly communicate, or initiate the communication of, theattribute information from the tag to the inquiry device.

A configurable monitoring device may also be configured by beingprovided configuration information via physical connection to aconfiguring device, such as a monitoring terminal. The physicalconnection may support the transmission of electrical signals betweenthe configuring device and the configurable monitoring device.Alternatively, if wireless configuring of configurable monitoringdevices is to be utilized to configure a plurality of devices, accordingto some example embodiments, the power of the signals including theconfiguration information may be precisely set, so as not to configureconfigurable monitoring devices that were not intended to be configured.

After being initially configured, the configurable monitoring device 10may be considered to be “commissioned”. In this regard, commissioning ofthe configurable monitoring device 10 may include providing theconfigurable monitoring device 10 with an initial configuration asdefined by its assigned role/mode. However, in some instances, analready configured device may be commissioned by modifying existingconfiguration information, replacing the existing configurationinformation, and/or providing additional hardware in communication withthe configurable monitoring device 10 to add further functionalcapabilities, and/or guidance for operation. The commissioning process,which may be handled internally by the configuration manager 24, mayinclude providing the configurable monitoring device 10 withconfiguration information or identifying configuration information(e.g., pre-stored configuration information) to be employed. However, insome cases, the commissioning process may further include providing theconfigurable monitoring device 10 with information directing changes toan already existing configuration of the configurable monitoring device10. This may occur, for example, when a commissioned configurablemonitoring device is to be re-tasked for use with another product ratherthan being decommissioned. In such a situation, since there is alreadyexisting information that is changed, the operation of changing theexisting configuration may be viewed as re-commissioning. Thecommissioning (or re-commissioning) may be accomplished via wirelessinstructions received by the communication interface. Commissioning mayalso be provided via scanning of an RFID tag, reading a barcode, addingspecialized hardware, bringing the configurable monitoring device 10into proximity of specialized hardware, etc.

In some example embodiments, a configurable monitoring device may befirst configured as a tag, and the tag may then be commissioned. Tocommission a tag, the following example procedure may be undertaken. Thetag may be first affixed to an article and brought into close proximityto a commissioning node. The commissioning node may communicate directlywith the tag via wireless communications when the tag is brought intorange of the commissioning node. While the tag is within range of thecommissioning node, a barcode scanner connected to the commissioningnode may be used to scan the barcode of the article to which the tag isaffixed. By scanning the barcode, a barcode to tag relationship may bedefined. Having generated the tag/barcode relationship, the tag may beconsidered commissioned. The tag/barcode relationship may be stored onthe tag and/or on memory storage accessible to a monitoring terminalthat oversees the operation of the monitoring system. Upon beingcommissioned, the tag may be configured to confirm the propercommissioning by generating an audible sound, such as two beeps.

While commissioned, the configurable monitoring device 10 may continueto receive instructions (e.g., via the communication interface 22) orother information useful for making determinations as to theconfiguration to be employed and the corresponding role/mode ofoperation to assume. However, in some cases, information useful formaking determinations regarding configuration changes (e.g., mode and/orrole shifts) may be made responsive to activity that may be sensed(e.g., via sensor 50 of FIG. 1B) or determined locally.

Decommissioning of the configurable monitoring device 10, which may alsobe handled by the configuration manager 24, may include powering downthe configurable monitoring device 10, clearing or resettingconfiguration information, or directing the configurable monitoringdevice 10 to enter an idle or non-transmitting mode in order to conservebattery power until the configurable monitoring device 10 isre-commissioned. The configurable monitoring device 10 may bedecommissioned by instructions received via the communication interface22 (e.g., via a software or coded key) or by manual activity taken by auser (e.g., with a physical key). Upon being decommissioned, a tag mayenter a forever sleep mode, until, for example, a switch on the tag isactuated by a user.

According to some example embodiments, a battery check may be performedby the processor 20 of a configurable monitoring device configured as atag during decommissioning. In this regard, the tag may include thehardware and software (e.g., processor configured by instructions) toprovide for monitoring the battery charge level. If the battery chargelevel for a tag has fallen below a given threshold, the tag may alarm orotherwise indicate to the store personnel that the tag should be removedfrom service for recharging or battery replacement. Tags that havebattery levels above the given threshold may be decommissioned andidentified as being available for re-commissioning. According to someexample embodiments, a tag having a battery level that has fallen belowa given threshold may be prevented from being re-commissioned until thebattery charge level is sufficient improved. In this manner, thesituation where a tag's battery discharged while the tag is not salesfloor can be minimized or avoided.

Accordingly, in general terms, the configurable monitoring device 10 maybe dynamically configurable via wireless instructions to alter theoperating mode of the configurable monitoring device 10 and thereby alsomodify the role of the configurable monitoring device 10 in its networkenvironment. The different configurations that are available at theconfigurable monitoring device 10 may be changed dynamically as well andmay be managed by the configuration manager 24. Thus, the configurationmanager 24 (e.g., via execution of stored instructions by the processor20) may provide control over the operation of the configurablemonitoring device 10 based on the configuration information storedand/or received at the configurable monitoring device 10 and, in somecases, also or alternatively based on local conditions sensed at theconfigurable monitoring device 10.

Some configurations in which the configurable monitoring device 10operates may specify specific alarm conditions to be triggered. As such,when alarm conditions are triggered based on the current configuration,the configuration manager 24 may communicate with the alarm module 26 tomanage alarm function of the alarm 42. The alarm 42 may be configured toproduce an output, typically in the form of sound energy, althoughlight, vibration or other outputs are also possible. As such, the alarm42 may include an output device such as one or more of a speaker,vibration pack, light (e.g., a light emitting diode (LED)) or otherdevice. The alarm module 26 may be configured to control operation ofthe alarm 42 based on instructions received from the configurationmanager 24. In this regard, based on the current configuration of theconfigurable monitoring device 10 as determined by the configurationmanager 24, an alarm condition may be identified and signaled to thealarm module 26. In some embodiments, the alarm condition may beassociated with a predetermined alarm signal, which the alarm module 26may be configured to provide to the alarm 42 to direct an output. Thealarm 42 may be configured to provide any number of different outputs inresponse to the alarm signal including but not limited to a tone orseries of tones, a ringing noise, a recorded or synthetic voice output,a solid or flashing light with any of various predetermined flashsequences, a vibration that is either continuous or pulsed with variousdifferent pulse sequences, or various other outputs or combinations ofthe above and/or other outputs.

In some embodiments, the alarm module 26 may provide alarm responsesthat are not necessarily just audible, light or mechanical vibrationoutputs. In this regard, for example, the alarm module 26 may beconfigured to further provide alerts to monitoring devices (e.g., analarm panel, a network monitoring server or computer and/or a localcomputer or server). The alerts may be text alerts describing acorresponding situation that triggered the alert. However, in othercases, the alerts may go to an alarm panel to be indicated bypre-configured light sequences, etc. As such, for example, when certainconditions or stimuli are encountered, the alarm module 26 may beconfigured to provide an alert that may be reviewed and either actedupon or noted and cleared by monitoring or management personnel. In someembodiments, the alerts may be routine alerts such as maintenancewarnings, low battery indications, or other network or system relatedalerts. However, the alerts could also have a marketing purpose in someembodiments. In this regard, specific activity may trigger an alert to acustomer that a related item is on sale, trigger asking the customerwhether a particular type of assistance may be offered, or may triggeran identification of a matching item and its location via a videodisplay proximate to the product being inspected by a customer andincluding the configurable monitoring tag.

In an exemplary embodiment, the alarm module 26 may merely direct, forall alarm conditions, a single response (e.g., one of the above listedalarm outputs). However, in an exemplary embodiment, the alarm responsegenerated by the alarm 42 may vary based on the current situation. Thus,for example, the configuration manager 24 may provide the alarm module26 with information identifying a specific alarm response (e.g., aselected one or combination of the above listed possible alarm outputs)to be provided based on the current mode of operation of theconfigurable monitoring device 10. In some cases, the identifiedspecific alarm response identified may be identified based at least inpart on current conditions associated with the current mode ofoperation. Thus, for example, the current mode of operation may defineno alarm response unless a specific stimulus is encountered. In responseto the stimulus being encountered locally (e.g., via informationprovided by the sensor 50) or remotely (e.g., via information providedthrough the communication interface 22), the configuration manager 24may signal the alarm module 26 to select an appropriate alarm response.The alarm 42 may therefore be employed for a variety of reasons due tothe flexibility associated with the alarms that may be provided and theconditional awareness associated with generation of the alarm responses.For example, the alarm 42 may be used to identify product location for aproduct near the configurable monitoring device 10 or a product to whichthe configurable monitoring device 10 is affixed. Alternatively, thealarm 42 may be used to signal a potential theft situation or even thepresence (e.g., within a relatively short distance) of anotherconfigurable monitoring device that may be in the process of beingstolen, tracked, or located.

The sensor 50 may be an optional device added to the configurablemonitoring device 10 in some situations (e.g., including optionalhardware that can be placed in operable communication with theconfigurable monitoring device 10). In this regard, the sensor 50 couldbe used for making determinations of local conditions at theconfigurable monitoring device 10. The sensor 50 could be embodied asany of various sensing devices configured to detect motion, light,images, sound, or other environmental stimuli. As such, the sensor 50may include a light detector, an optical scanner, a motion detector orother sensing devices. In an exemplary embodiment, the sensor 50 may beconfigured to detect a particular indicia of attempts to remove theconfigurable monitoring device 10 from a product to which theconfigurable monitoring device 10 is affixed or of other attempts tosteal the product. As such, for example, if a particular type of productto which the configurable monitoring device 10 is affixed is typicallysusceptible to handling in a specific manner by thieves attempting toconceal the product being stolen, remove the configurable monitoringdevice 10 from the product, or damage the product, the sensor 50 may beconfigured to sense indicia of the corresponding handling Thus, forexample, in response to the configurable monitoring device 10 being in atheft deterrent related mode when the indicia of the correspondinghandling indicative of improper activity is received, the sensor 50 mayprovide a signal to the configuration manager 24 to indicate the currentconditions to enable the configuration manager 24 to alter the operationof the configurable monitoring device 10 accordingly (e.g., byinstructing the alarm module 26 to generate an alarm response at thealarm 42 that is indicative of the respective improper activity.

The battery 40 may be any type of battery or battery pack that providessufficient power to permit extended operation of the configurablemonitoring device 10. The battery 40 may be rechargeable or replaceableand may be of any suitable size. In some embodiments, the battery 40 mayhave terminals that extend from a casing or housing of the configurablemonitoring device 10 to enable the configurable monitoring device 10 tobe placed on a charging stand. In some situations, a single or multipleelement charging stand may be provided to enable out of service (or somein service) configurable monitoring devices to be recharged. Theterminals may also enable wired communication with the configurationmanager 24 to enable the provision of configuration information to theconfigurable monitoring device 10 via the charging stand while thebattery 40 is being charged or otherwise when the configurablemonitoring device 10 is being commissioned, re-commissioned or evenwhile the configurable monitoring device 10 is decommissioned. In someexample embodiments, such as when the configurable monitoring device isconfigured to operate as a stationary node, a configurable monitoringdevice may alternatively, or additionally, include a mains powerconnection for powering the configurable monitoring device.

As indicated above, the configurable monitoring device 10 may, in somecases, operate in a tag mode. When operating in a tag mode, it may oftenbe desirable for the configurable monitoring device 10 to be affixed toa particular product or retail article. When operating in node mode, itmay be desirable for the configurable monitoring device 10 to bedisposed at a centralized location relatively near to a plurality oftags or otherwise strategically located at a selected location tofacilitate communication with and/or information extraction from tags.However, exceptions to the situations described above are permissibleand may in fact be common in many exemplary architectures employingembodiments of the present invention. In any case, the configurablemonitoring device 10 may include a mounting device 52 to facilitateplacement of the configurable monitoring device 10.

In situations where the configurable monitoring device 10 is affixed toa product or retail article, the mounting device 52 may be configured tobe tailored to providing an appropriate mechanism of affixing theconfigurable monitoring device 10 to the corresponding product. As such,for example, in some situations, an adhesive, snap fastener, clip,clasp, tether, hook-and-loop fastener, magnetic fastener, pin connector,or other fastening device enabling direct connection of the configurablemonitoring device 10 to the corresponding product may be provided as themounting device 52. One such mounting device may be configured to attachto the shaft of a golf club or similar article such as the devicedisclosed in U.S. Pat. No. 7,266,979 herein incorporated by reference inits entirety. Other such mounting devices may be configured to attach toa bottle neck or a bottle cap such as the devices disclosed in U.S. Pat.Nos. 7,259,674 and 7,007,523, both herein incorporated by reference intheir entirety. Still other mounting devices may be configured to attachthrough a product such as an article of clothing or a blister pack suchas the hard-tag disclosed in U.S. Pat. No. 6,920,769 incorporated hereinby reference in its entirety. Each of the aforementioned patents iscommonly owned by the assignee of the present application.

However, in other situations, some products may not be suitable fordirect attachment to the product. For example, while a product such as agolf club, bottle, shoe or article of clothing may be suitable for theattachment via direct connection thereto, articles that are sold in apackaging box are often less suitable for such attachment. In thisregard, packaging boxes may be opened and the article therein may thenbe stolen without the box. Moreover, it may not be practical ordesirable to open packaging in order to directly connect theconfigurable monitoring device 10 to the product. Accordingly, in someembodiments, the mounting device 52 may actually be a wrap such as AlphaSecurity Products' Spider Wrap™ disclosed in U.S. Pat. No. 7,162,899herein incorporated by reference in its entirety. Further, a cable lock,such as the Alpha Security Products' Cablelok™ device disclosed in U.S.Pat. No. 7,249,401 or a keeper, such as that disclosed in U.S. Pat. No.6,832,498 may include the configurable monitoring device 10. Each of theaforementioned patents being commonly owned by the assignee of thepresent application and herein incorporated by reference in theirentirety. The wrap may be particularly useful in connection withsix-sided box packaging for larger articles. The enclosure (or keeper)may be particularly useful for smaller articles such as CDs, DVDs,bottles, tubes or other containers of health, beauty and/or otherproducts.

Depending on the type of mounting device 52, a configurable monitoringdevice configured as a tag may be configured to operate differently. Forexample, a hard tag may be aimed to alarm by insertion of a pin toactivate or arm the alarm. The hard tag may then alarm when the pin isviolated. A CableLok™ device may be armed in response to a bayonet beinginserted and the continuity of the bayonet may be monitored such thatthe device is configured to alarm in response to the bayonet being cutand the continuity being disrupted. SpiderWraps™ may also alarm inresponse to a cable being cut. Keepers may arm via a slide switch andmay alarm in response to the lid of the keeper being violated.

In some applications, the mounting device 52 may be unlockable by theimplementation of a key. The key may be embodied in many different ways.In this regard, in some situations, the key may be a specially formeddevice that mates mechanically with some portion of the mounting device52 in order to disable a locking mechanism of the mounting device 52. Asan alternative, the key may be a magnetic device configured to interfacewith a locking mechanism of the mounting device 52 to enable themounting device 52 to be unlocked to permit removal of the mountingdevice 52 from the corresponding product to which the mounting device 52is affixed. As yet another alternative, the key may actually include anelectrical component for exchanging signals or information with themounting device 52 to enable unlocking of the mounting device 52. Assuch, for example, the key could be an embodiment of the configurablemonitoring device 10 that is provided with specific configurationinformation defining functionality for the configurable monitoringdevice 10 to function as the key for unlocking the mounting devices ofother configurable monitoring devices. In such implementations, the key(or the configuration information associated with the key) may include asoftware component or code that is unique to a particular individual(e.g., a specific manager or assistant manager). Furthermore, theconfigurable monitoring device 10 configured to function as a key mayreport unlocking activities and/or other information regarding otherdevices encountered or activities undertaken to a local or remotedatabase so that activity of the key may be monitored. Additionally,authenticity of the code may be defined or verified so that, forexample, if a particular manager's key is lost or a manager leaves, thecorresponding code for the manager's key may be invalidated so thatfurther unlocking operations with the manager's key may not be possible.In addition to or as an alternative to unlocking mounting devices, thekey may be useful for setting an alarm or turning an alarm on or off.

In some embodiments, the sensor 50 may be a portion of or otherwisepositioned to monitor activity with respect to the mounting device 52.Thus, for example, the sensor 50 may be configured to determine whetherthe enclosure is opened or the wrap is cut, stretched, mutilated orotherwise damaged. The sensor 50 may alternatively be configured todetermine whether the mounting device 52 is removed from thecorresponding product to which the mounting device 52 was attached.Accordingly, in response to the sensor 50 detecting attempts to removethe configurable monitoring device 10 from the product, the sensor 50may provide an indication to the configuration manager 24 (e.g., via theprocessor 20) and the configuration manager 24 may take appropriateaction (e.g., change the mode of operation of the configurablemonitoring device 10 or signal the alarm module 26 to issue an alarmresponse, and/or the like).

As indicated above, the mounting device 52 may, in some cases, notattach the configurable monitoring device 10 to a product. As such, themounting device 52 may alternatively comprise a stand, base or othersupport for enabling the positioning of the configurable monitoringdevice 10 in a desirable location. In some situations, the mountingdevice 52 may include an adhesive or other mechanism for attaching theconfigurable monitoring device 10 to a surface such as a ceiling, floor,desk, display case, table, platform, door, door jamb, vehicle, or otherstructure. When mounted to such structures, the configurable monitoringdevice 10 may often be operated in a node (router), hub or gateway mode.In an exemplary embodiment, by providing a configurable monitoringdevice on each door jamb of a building exit, the configurable monitoringdevices on each side of the door jamb may form an EAS gate.

In various embodiments, the configurable monitoring device 10 mayoperate in any of various different modes and therefore perform any ofvarious corresponding roles. Some examples of some of these modes willbe described in greater detail below. Multi-modal operation of theconfigurable monitoring device 10 may, in some cases, extend torelatively broad classifications that relate to correspondingoperational roles of the configurable monitoring device 10. For example,in some situations, the configurable monitoring device 10 may bedynamically configured to operate in accordance with roles defined for asecurity mode, a marketing mode, an inventory management mode, and/orthe like. Furthermore, each mode may include sub-modes. For example,some examples of sub-modes of operation may include a tag mode or nodemode, each with a corresponding role of acting as a tag or a node,respectively. Some embodiments may permit definition of additionalsub-modes and corresponding roles such as, for example, operation as ahub or gateway. However, in alternative embodiments, tag mode, node modeand other modes of operation may themselves be primary modes ofoperation and not necessarily sub-modes.

FIG. 1C shows an example of a flow diagram illustrating configuration ofthe configurable monitoring device according to an exemplary embodiment.In this regard, as shown in FIG. 1C, a configurable monitoring devicemay initially be powered up (or initialized) at operation 200.Subsequent to power up or initialization, the configurable monitoringdevice may check for configuration information at operation 202. Ifconfiguration information is found, the configurable monitoring devicemay configure itself according to the configuration information found atoperation 204. If no configuration information is found, theconfigurable monitoring device may either request configurationinformation from the nearest node or gateway at operation 206 or simplywait to receive configuration information and enter an idle mode in themeantime at operation 208. At operation 210, either in response to arequest for configuration information or responsive to direction toprovide configuration information to the configurable monitoring devicethat is either manually or automatically generated, the configurablemonitoring device may receive configuration information. Reception ofconfiguration information may trigger the configurable monitoring deviceto configure itself according to the configuration information found atoperation 204. After being configured, the configurable monitoringdevice may monitor activity according to the configuration informationat operation 212. At any time during monitoring, new configurationinformation may be received to trigger reconfiguring of the configurablemonitoring device at operation 204. However, during monitoring, any oneof several occurrences may be encountered. For example, the configurablemonitoring device could be decommissioned at operation 214 or reportactivity to another configurable monitoring device (e.g., a node,gateway or hub) or an external device at operation 216. In some cases, aspecific stimulus may be detected at the configurable monitoring deviceor the configurable monitoring device may receive notification of thestimulus from another configurable monitoring device at operation 218.In response to the detection of the stimuli, the configurable monitoringdevice may report the activity at operation 216 or take action accordingto the configuration information (e.g., as defined by the configurationmanager 24) at operation 220.

FIG. 2 illustrates basic block diagram of a monitoring terminal 62according to an exemplary embodiment. As shown in FIG. 2, the monitoringterminal 62 may include various components that support both the basicoperation of the monitoring terminal 62 and the relatively moresophisticated operation of the monitoring terminal 62 as a coordinatorof a monitoring system. Some examples of these components are shown inFIG. 2. However, it should be appreciated that some example embodimentsmay include either more or less than the example components illustratedin FIG. 2. Thus, the example embodiment of FIG. 2 is provided by way ofexample and not by way of limitation.

Reference will now be made to FIG. 2 to describe an example structureand functional operation of the monitoring terminal 62 according to anexemplary embodiment. In this regard, as shown in FIG. 2, the monitoringterminal 62 may include a processor 1250 and a communication interface252. In some example embodiments, the monitoring terminal 62 may includea user interface 258. The processor 1250 may in turn communicate with,control or embody (e.g., via operation in accordance with correspondinginstructions) a monitoring system manager 256.

In an exemplary embodiment, the processor 1250 may be configured (e.g.,via execution of stored instructions or operation in accordance withprogrammed instructions) to control the operation of the monitoringterminal 62. The processor 1250 may be embodied in a number of differentways. For example, the processor 1250 may be embodied as one or more ofvarious processing means or devices such as a coprocessor, amicroprocessor, a controller, a digital signal processor (DSP), aprocessing element with or without an accompanying DSP, or various otherprocessing devices including integrated circuits such as, for example,an ASIC (application specific integrated circuit), an FPGA (fieldprogrammable gate array), a microcontroller unit (MCU), a hardwareaccelerator, a special-purpose computer chip, or the like. In anexemplary embodiment, the processor 1250 may be configured to executeinstructions stored in a memory device (e.g., memory device 254 of FIG.2) or otherwise accessible to the processor 1250. The instructions maybe permanent (e.g., firmware) or modifiable (e.g., software)instructions. Alternatively or additionally, the processor 1250 may beconfigured to execute hard coded functionality. As such, whetherconfigured by hardware or software methods, or by a combination thereof,the processor 1250 may represent an entity (e.g., physically embodied incircuitry) capable of performing operations according to embodiments ofthe present invention while configured accordingly. Thus, for example,when the processor 1250 is embodied as an ASIC, FPGA or the like, theprocessor 1250 may be specifically configured hardware for conductingthe operations described herein. Alternatively, as another example, whenthe processor 1250 is embodied as an executor of software or firmwareinstructions, the instructions may specifically configure the processor1250 to perform the algorithms and/or operations described herein whenthe instructions are executed. The processor 1250 may include, amongother things, a clock, an arithmetic logic unit (ALU) and logic gatesconfigured to support operation of the processor 1250.

The memory device 254 may include, for example, one or more volatileand/or non-volatile memories. In other words, for example, the memorydevice 254 may be an electronic storage device (e.g., acomputer-readable storage medium) comprising gates (e.g., logic gates)configured to store data (e.g., bits) that may be retrievable by amachine (e.g., a computing device including a processor such asprocessor 1250). The memory device 254 may be configured to storeinformation, data, applications, instructions or the like for enablingthe monitoring terminal 62 to carry out various functions in accordancewith exemplary embodiments of the present invention. For example, thememory device 254 could be configured to buffer input data forprocessing by the processor 1250. Additionally or alternatively, thememory device 254 could be configured to store instructions forexecution by the processor 1250.

The user interface 258 may be in communication with the processor 1250to receive user input via the user interface 258 and/or to presentoutput to a user as, for example, audible, visual, mechanical or otheroutput indications. The user interface 258 may include, for example, akeyboard, a mouse, a joystick, a display (e.g., a touch screen display),a microphone, a speaker, or other input/output mechanisms. Further, theprocessor 1250 may comprise, or be in communication with, user interfacecircuitry configured to control at least some functions of one or moreelements of the user interface. The processor 1250 and/or user interfacecircuitry may be configured to control one or more functions of one ormore elements of the user interface through computer programinstructions (e.g., software and/or firmware) stored on a memoryaccessible to the processor 1250 (e.g., volatile memory, non-volatilememory, and/or the like). In some example embodiments, the userinterface circuitry is configured to facilitate user control of at leastsome functions of the monitoring terminal 62 through the use of adisplay configured to respond to user inputs. The processor 1250 mayalso comprise, or be in communication with, display circuitry configuredto display at least a portion of a user interface, the display and thedisplay circuitry configured to facilitate user control of at least somefunctions of the monitoring terminal 258.

The communication interface 252 may be any means such as a device orcircuitry embodied in either hardware, software, or a combination ofhardware and software that is configured to receive and/or transmit datafrom/to a network and/or any other device or module in communicationwith the monitoring terminal 62. According to some example embodimentswhere the monitoring terminal 62 is directly connected to the monitoringsystem, the communications interface 252 may include an appropriatelyconfigured configurable monitoring device. Further, the communicationinterface 252 may include, for example, an antenna (or multipleantennas) and supporting hardware and/or software for enablingcommunications with a wireless communication network 30 or other devices(e.g., other configurable monitoring devices). In some environments, thecommunication interface 252 may alternatively or additionally supportwired communication. As such, for example, the communication interface252 may include a communication modem and/or other hardware/software forsupporting communication via cable, digital subscriber line (DSL),universal serial bus (USB) or other mechanisms.

In an exemplary embodiment, the communication interface 252 may supportcommunication via one or more different communication protocols ormethods. In some embodiments, the communication interface 252 may beconfigured to support relatively low power, low data rate communication.As such, for example, a low power and short range communication radio(e.g., radio transmitter/receiver) may be included in the communicationinterface 252. In some examples, the radio transmitter/receiver mayinclude a transmitter and corresponding receiver configured to supportradio frequency (RF) communication in accordance with an IEEE (Instituteof Electrical and Electronics Engineers) communication standard such asIEEE 802.15. As such, for example, some embodiments may employBluetooth, Wibree, ultra-wideband (UWB), WirelessHART, MiWi or othercommunication standards employing relatively short range wirelesscommunication in a network such as a wireless personal area network(WPAN). In some cases, IEEE 802.15.4 based communication techniques suchas ZigBee or other low power, short range communication protocols suchas a proprietary technique based on IEEE 802.15.4 may be employed.

In an exemplary embodiment, the communication interface 252 mayadditionally or alternatively be configured to support communication viaradio frequency identification (RFID) or other short range communicationtechniques. Accordingly, the monitoring terminal 62 may be configured tointerface configurable monitoring devices, in addition to conventionalRFID tags and modules. In another embodiment, the monitoring terminal 62may be configured to interface a barcode scanner, or other data entrydevices.

As mentioned above, monitoring terminal 62 may be directly connected tothe monitoring system via a configurable monitoring device configured asa gateway, or the monitoring terminal 62 may be connected to themonitoring system 60 via a gateway and an external network 30. Thenetwork 30 to which the communication interface 252 may connect may be alocal network (e.g., a WPAN) that may in some cases further connect toor otherwise communicate with a remote network on either a periodic orcontinuous basis. The network 30 may include a collection of variousdifferent nodes, devices or functions that may be in communication witheach other via corresponding wired and/or wireless interfaces.

As indicated above, the processor 1250 of the monitoring terminal 62 maybe embodied as, include or otherwise control the monitoring systemmanager 256. The monitoring system manager 256 may be any means such asa device or circuitry operating in accordance with firmware/software orotherwise embodied in hardware or a combination of hardware andfirmware/software (e.g., processor 1250 operating under softwarecontrol, the processor 1250 embodied as an ASIC or FPGA specificallyconfigured to perform the operations described herein, or a combinationthereof) thereby configuring the device or circuitry to perform thecorresponding functions of the monitoring system manager 256, asdescribed herein. Thus, in examples in which software is employed, adevice or circuitry (e.g., the processor 1250 in one example) executingthe software forms the structure associated with such means.

The monitoring system manager 256 of the monitoring terminal may beconfigured to coordinate, manage, and configure the operation ofconfigurable monitoring devices. In this regard, the monitoring systemmanager 256 may be configured to perform a number of activities withregard to a monitoring system as further described below and otherwiseherein. While the monitoring system manager 256 may be configured toperform all of the functionality described with respect to themonitoring system manager 256 herein, it is also contemplated that themonitoring system manager 256 could be configured to perform any sub-setof the described functionality.

The configuration information may include role policy information thatindicates the functionality that the configurable monitoring deviceshould perform within the device's assigned role, and attributeinformation, such as associated product attributes. Attributeinformation may be data that a configurable monitoring device mayutilize within the role to perform functionality. For example, if aproduct that the configurable monitoring device is affixed to isclothing, the attribute information may include a clothingclassification (e.g., shirt, pants, tie, dress, etc.), a color or colorsindicator, a size indicator, a price indicator, a lot indicator, and thelike. Based on the attribute information, the functionality performed bya configurable monitoring device may be determined. For example,configurable monitoring devices configured with the same role policyinformation, may trigger different types of alarm responses based on theprice of the product. According to some example embodiments, attributeinformation may be stored in a central location, rather than at theconfigurable monitoring device, and the configurable monitoring devicesmay access this information remotely via the network of the monitoringsystem as needed.

According to some example embodiments, the configuration information mayinclude executable code that is, possibly decompressed, and stored onthe configurable monitoring device for subsequent execution by theconfigurable monitoring device. However, in some example embodiments, aconfigurable monitoring device may be manufactured with executable codein the form of configuration information stored within the memory of thedevice. Alternatively, a hardware device, such as a memory device orpreconfigured processing device with pre-stored configurationinformation may be inserted into and/or electrically connected to theconfigurable monitoring device to provide configuration information andassign a role to the configurable monitoring device. The pre-storedconfiguration information may be directed to a number of possible rolesthat the configurable monitoring device could be configured to perform.In this regard, to configure the configurable monitoring device, themonitoring system manager 256 may provide a message including anindicator of which role the configurable monitoring device is toperform. The configurable monitoring device may receive the indicatorand begin performing the role described by the indicator by executingthe appropriate portion of the pre-stored configuration information.

In addition or as an alternative, the gateway node (G) may be incommunication with a monitoring terminal (MT) 190. The monitoringterminal 190 may be a computing device such as a laptop, PC, server orother terminal to which information exchanged within the mesh network isreported and from which information may be received. In someembodiments, the monitoring terminal 190 may include a database and/orother information recording devices configured to record activityreported by the nodes. For example, movement of tags, product and/ormarketing information received from tags or provided responsive tomovement of tags, tag position and/or position history, mode changes,configuration changes and other information may be recorded formonitoring by store personnel or other operators either locally orremotely. Furthermore, in some cases, the monitoring terminal 190 may beused to interface with tags or nodes by providing configurationinformation for communication to specific tags and/or nodes. As such,according to an exemplary embodiment, the monitoring terminal 190 mayalso include at least a display and user interface to enable anapplication with a graphical user interface (GUI) tailored to enablingmonitoring activities associated with and/or communicating withconfigurable monitoring devices. Accordingly, the GUI may also beconfigured to enable use of the monitoring terminal 190 for definingconfiguration information for provision to the tags or nodes.

Once a configurable monitoring device is assigned a role via theconfiguration information, the device may begin operating within itsrespective role. Roles or configurations may be simple or complex basedon, for example, the processing capabilities and the memory storageavailable to a configurable monitoring device. In this regard, aconfigurable monitoring device may be configured to perform minimal dataprocessing, and the monitoring terminal 190 may be configured to performincrementally more processing of data. Alternatively, some configurablemonitoring devices may include relatively higher processing power andlarger memory storage to support increased data processing at theconfigurable monitoring device, rather than at the monitoring terminal190.

Alternatively, in embodiments where the configurable monitoring deviceincludes a relatively large storage memory, attribute informationdescribing the article to which a configurable monitoring device isaffixed may be stored local to the tag, within the storage memory of thetag. When an inquiry device (e.g., price scanner, inventory scanner)requests the attribute information from the tag, the tag may directlycommunicate, or initiate the communication of, the attribute informationfrom the tag to the inquiry device.

The following describes some of the roles that may be implemented by theconfigurable monitoring devices and the interactions that may involvethe monitoring terminal 62 and the monitoring system manager 256 whilethe configurable monitoring devices are operating within their roles. Asdescribed above, and generally herein, a configurable monitoring devicemay include a processor and a memory. The processor may be configured tosupport network communications. According to various exampleembodiments, the processor may be configured, for example, viainstructions stored on the memory (e.g., instructions derived fromconfiguration information), to support communications in accordance witha role defined by configuration information. Further, the processor ofthe configurable monitoring device may include input/output (I/O) ports(or pins). Via configuration information, the I/O ports may beconfigured to interface with any number of external devices such as,electronic security devices, alarms, speakers, microphones, lights(e.g., light emitting diodes (LEDs)), buttons, keypads, monitors,displays (e.g., for changeable pricing labels), sensors (e.g.,accelerometers, movement sensors, light sensors, temperature sensors),cameras, security gates, store audio systems, customer counters,lighting switches, employee communicators (e.g., headsets, handheldradios), door strike mats, jewelry case mats, Lojack® devices, globalpositioning system (GPS) devices, and the like. As such, the I/O portsmay be configured to support one or more roles that the configurablemonitoring device may be configured to perform.

Via the I/O ports of the processor, various functionalities may betriggered, based on the role and the configuration information of theconfigurable monitoring device. Following from the discussion above,triggering may be initiated either at the configurable monitoring devicelevel or at the monitoring terminal level. For example, the I/O ports ofa configurable monitoring device's processor may interface with adisplay for a price tag, when the configurable monitoring device isconfigured as a tag. Within the tag's configured role, for example, theprice depicted on the display may be set to reduce at a given time. Insome example embodiments, the time may monitored by the processor of thetag and when the given time is reached, the processor may direct the I/Oports and the connected display to depict a reduced price.Alternatively, an example that includes triggering at the monitoringterminal level may include the time being monitored by the monitoringterminal, and the monitoring terminal may communicate a messageincluding a reduced price, or an indication to reduce the price, to thetag at the given time to trigger the tag to reduce the priceaccordingly.

While the roles described herein may be considered from the perspectiveof an implementation in a retail sales environment, the scope of theinvention should not be limited to such implementations. For ease ofunderstanding, FIG. 3, which illustrates an example retail environment100, is referred to in order to describe some of the roles that may beimplemented by the configurable monitoring devices within an exemplarymonitoring system.

FIG. 3 illustrates a diagram of various configurable monitoring devicesconfigured to define a monitoring system. In this regard, FIG. 3 depictsan exemplary retail environment 100 including a stock room 110 whereexcess inventory is maintained, an office space 120 from whichmonitoring activity may be coordinated or otherwise viewed (e.g., via amonitoring terminal 62), fitting rooms 130 in which articles of clothingmay be tried on by potential buyers, a retail floor 140 on which variousproducts may be displayed or otherwise made available for buyers topurchase and restrooms 150. FIG. 3 also depicts a point of sale (POS)terminal 160 at which payment may be made for products and a door 170through which customers may enter and exit the retail floor 140.

Within a retail environment application, various different products mayeach be provided with a corresponding configurable monitoring deviceoperating as a tag. Furthermore, several other configurable monitoringdevices may be provided at various locations throughout the retailenvironment to operate, for example, as nodes. In this regard, thelocation of a node within the retail environment may be known (e.g.,coordinates of the nodes may be known) to, for example, the monitoringterminal 62 and the monitoring system manager 256 to facilitateimplementation of a real-time location system (RTLS) for the tags viathe nodes. Several configurable monitoring devices operating in a tagmode are illustrated in FIG. 3 as circles with the letter “T” therein.Some other configurable monitoring devices may be configured duringcommissioning to operate in a node mode. Examples of configurablemonitoring devices operating in node mode are shown in FIG. 3 as circleswith the letter “N” therein. Still others (or a single configurablemonitoring device) may be configured to operate as gates or in a hub orgateway mode. While configurable monitoring devices may be configured astags, nodes, gateways, etc., each of these roles may be further refined,for example via configuration information, to specialize thefunctionality of a configurable monitoring device within a particularrole.

To join the monitoring system, a configurable monitoring device mayfirst be associated with the monitoring system. To associate theconfigurable monitoring device to a monitoring system, and join thecommunications network of the monitoring system, a configurablemonitoring device to be associated may perform an association procedure,such as the example association procedure depicted in FIG. 12. Toassociate a configurable monitoring device a network coordinator may beutilized. A messaging procedure, such as the procedure described in FIG.12 may be performed between the coordinator and the associated device.The associated device may provide MAC layer association procedures as aservice to the network (NWK) layer. The NWK layer may manage the networkformation. Similarly, FIG. 13 depicts an example dissociation procedurefor use when a configurable monitoring device intends to leave thenetwork.

Various techniques may be utilized to associate and dissociate aconfigurable monitoring device. For example, a specific networkidentifier (e.g., PAN ID) may be provided to the configurable monitoringdevice at manufacturing. Further, low transmission power association anddissociation may be implemented using close proximity signaling.Further, hardware, switches (e.g., DIP (dual in-line processor)switches), jumpers, MAC address filtering, button actuatedassociation/dissociation, separate communications linkassociating/dissociating, or a barcode scanners may be used forassociated or dissociated.

A configurable monitoring device configured to operate as a tag mayperform functionalities supporting security functions, inventoryfunctions, marketing functions, combinations thereof, and the like. Inthis regard, subsequent to configuring a configurable monitoring deviceas a tag, a commissioning or binding procedure may be performed. Priorto commissioning, a configurable monitoring device may be configured asa tag, but the device may not yet be associated with, or affixed to, aproduct. Upon associating the tag with a product, the tag may becommissioned. The monitoring terminal 62 and the monitoring systemmanager 256 may manage the commissioning and decommissioning of tags viawireless communications with the tags. For example, the procedure forcommissioning and decommissioning a tag may include RFID scanning thetag, a barcode scanning the tag, and/or hardware (e.g., specializedmicrochip) attachment or connection.

To commission a tag, the monitoring system manager 256 may provide asignal to the tag indicating that the tag is now active with respect toits configured role. In this regard, alarming, inventory, and marketingfunctionality may be activated. While commissioned, the tag may continueto receive instructions or other information useful for makingdeterminations as to the functionality to be employed and thecorresponding role/mode of operation to assume.

Decommissioning of the tag may include powering down the tag, clearingor resetting data (e.g., product specific information), or directing thetag to enter an idle or non-transmitting mode in order to conservebattery power until the tag is re-commissioned. The tag may bedecommissioned by instructions and/or signals received from themonitoring terminal 62 and the monitoring system manager 256.

Decommissioning may occur at a point of sale, such as POS 160. A nodeassociated with the point of sale (POS node) may be configured, viaconfiguration information, to perform decommissioning functionality. Inthis regard, the POS node may be configured to decommission the tag whenthe product is entered into a sales transaction. The monitoring systemmanager 256 may be configured to interface with a sales database or salesystem to monitor transactions. Upon detecting a transaction, data aboutthe product involved in the transaction may be acquired, and, based onthe acquired data, a decommission signal may be transmitted to theaffected tag. According to some example embodiments, direct access to asales database or sales system may not be available due to concernsregarding the confidentiality of sales and customer information. Inthese situations, example embodiments of the present invention mayimplement a barcode scanning wedge as an interface to the transactionactivities without accessing the sales database or sales system.

According to some example embodiments, a battery check may be performedby a tag during decommissioning. In this regard, the configurablemonitoring device may include the hardware and software (e.g., processorconfigured by instructions) to provide for monitoring the battery chargelevel. If the battery charge level for a tag has fallen below a giventhreshold, the tag may alarm or otherwise indicate to the storepersonnel that the tag should be removed from service for recharging orbattery replacement. Tags that have battery levels above the giventhreshold may be decommissioned and identified as being available forre-commissioning. According to some example embodiments, a tag having abattery level that has fallen below a given threshold may be preventedfrom being re-commissioned until the battery charge level issufficiently improved. This would also desirably limit the need for astore clerk to retrieve low battery tags from the field or storeenvironment.

The barcode scanning wedge may be installed in-line between a barcodescanner and a point of sale checkout terminal for receiving dataacquired by the barcode scanner. The wedge may be configured tointercept some or all data acquired by the barcode scanner and toprovide the data to a monitoring system, for example, via a POS node,without otherwise interrupting the flow of data to the point of saleterminal.

The wedge may be configured to facilitate the commissioning ordecommissioning of a communications tag that is part of a monitoringsystem. For example, when a cashier scans a barcode of a product duringa purchase transaction, data confirming the transaction may be uploadedto the monitoring system and the monitoring system manager 256 via thewedge. Confidential consumer and sales information would not be uploadedto the retail security network. In response to receiving a salesconfirmation, the monitoring system manager 256 may be configured totransmit a decommission signal to an associated tag attached to thepurchased product to cause the tag to be decommissioned. Decommissioningmay be associated with removal of the tag from the product and/orremoval or modification of a record or information (e.g., inventoryinformation) for the tag stored by the monitoring system manager 256,for example, in the memory device 254.

A configurable monitoring device may also be configured as a manager'skey to be implemented within the monitoring system. FIG. 11 depicts anexample block diagram of a key, such as manager's key. The key of FIG.11 is depicted as using the Zigbee protocol, but any protocol may beused. In some applications, a mounting device that mechanically protectsa product may be unlockable by the implementation of a key. According tosome exemplary embodiments, the mounting device may be a pin tag (forprotecting a clothing), a keeper or plastic enclosure (for protectingcompact disks, software, cologne, and the like), a Spider Wrap™ or wirewrap device (for protecting larger boxed products), or the like. Onesuch mounting device may be configured to attach to the shaft of a golfclub or similar article such as the device disclosed in U.S. Pat. No.7,266,979 herein incorporated by reference in its entirety. Other suchmounting devices may be configured to attach to a bottle neck or abottle cap such as the devices disclosed in U.S. Pat. Nos. 7,259,674 and7,007,523, both herein incorporated by reference in their entirety.Still other mounting devices may be configured to attach through aproduct such as an article of clothing or a blister pack such as thehard-tag disclosed in U.S. Pat. No. 6,920,769 incorporated herein byreference in its entirety. Each of the aforementioned patents beingcommonly owned by the assignee of the present application.

As mentioned above, Alpha Security Products' Spider Wrap™, which isdisclosed in U.S. Pat. No. 7,162,899 and herein incorporated byreference in its entirety, may also be configured to operate as amounting device. Further, a cable lock, such as the Alpha SecurityProducts' Cablelok™ device disclosed in U.S. Pat. No. 7,249,401 or akeeper, such as that disclosed in U.S. Pat. No. 6,832,498 may be amounting device. Each of the aforementioned patents being commonly ownedby the assignee of the present application and herein incorporated byreference in their entirety.

The key may be embodied in many different ways. In this regard, in somesituations, the key may be a specially formed device that matesmechanically with some portion of the mounting device in order todisable a locking mechanism of the mounting device. As an alternative,the key may be a magnetic device configured to interface with a lockingmechanism of the mounting device to enable the mounting device to beunlocked to permit removal of the mounting device from the correspondingproduct to which the mounting device is affixed. As yet anotheralternative, the key may actually include an electrical component forexchanging signals or information with the tag associated with themounting device to enable unlocking of the mounting device. As such, forexample, the key could be an embodiment of a configurable monitoringdevice that is provided with specific configuration information definingfunctionality for the configurable monitoring device to function as thekey for unlocking the mounting devices of tags. In such implementations,the key (or the configuration information associated with the key) mayinclude a software component or code that is unique to a particularindividual (e.g., a specific manager or assistant manager).

The key may also report unlocking activities and/or other informationregarding other devices encountered or activities undertaken tomonitoring system manager 256, so that activity of the key (or personspossessing the key) may be monitored, logged, and/or tracked.Additionally, authenticity of the code may be defined or verified sothat, for example, if a particular manager's key is lost or a managerleaves, the corresponding code for the manager's key may be invalidatedso that further unlocking operations with the manager's key may not bepossible. With respect to the security of the key itself, the key may beconfigured to alarm and/or destroy necessary aspects of the key'sfunctionality if the key is, for example, improperly removed from theretail environment. For example, the key may clear the memory of thekey, rendering the key useless.

Utilization of the key for unlocking security devices may be limited byrules stored on the key or at a monitoring terminal. For example, rulesfor using the key may be defined with respect to the location of the key(e.g., inside/outside the store, inside/outside a department zone), theemployee using the key (e.g., as indicated by a pass code or detectionof a user's RFID tag), a time of day, a day of the week, a workschedule. Use of the key in violation of the rules may cause the key toalarm.

In addition to, or as an alternative to unlocking mounting devices, thekey may be useful for setting an alarm or turning an alarm on or off. Inthis regard, to utilize the key, a button on the key may be actuatedwhich indicates that the key is preparing to or is performing a lockingor unlocking function. An indication that the button has been pressedmay be commutated to the tag that is to be interacted with or themonitoring terminal. Further, in consideration of the locatingfunctionality described below, the key may be located and tracked, andzones of use (e.g., the key cannot be used in the stock room 110) andother rules may be defined and enforced with respect to the key.

According to some example embodiments, a configurable monitoring deviceconfigured as a tag, whether commissioned or decommissioned, may providea status signal (or heartbeat signal) to the monitoring system. Thestatus signal may be a short transmission of a unique identifier for thetag. The status signal may be provided an indication that a battery isnot yet drained or that the tag is otherwise properly functioning. Thestatus signal may also be used for RTLS purposes as further describedbelow. The status signal may be received by the monitoring systemmanager 256. The monitoring system manager 256 may maintain a log of themost recent receipt of a status signal from a tag. If the tag fails toprovide a status signal within a threshold period of time, an alarm orerror indication may be generated.

According to some example embodiments, nodes of the monitoring systemmay be configured to provide beacon signals. The tags may be configuredto receive a beacon signal and communicate information in response toreceipt of a beacon signal. For example, battery status, alarm status,received signal strength, and the like may be provided in response to abeacon signal.

As alluded to above, within the role of a tag various functionalitiesmay be implemented, such as advanced security functionalities. Forexample, complex alarming conditions may be defined for a tag based ondata received from sensors on the tag, location information, movementinformation, and the like. For example, tags may be configured tooperate as or with EAS tags, such that when the tag passes through anEAS gate, the EAS gate may detect the tag (or a connected EAS tag), andpossibly sound an alarm. According to some example embodiments, themonitoring terminal 62 may have received a communication regarding thealarm condition.

With regard to operation within EAS systems, configurable monitoringdevices may be configured to operate as tags to be detected, or as gatenodes for detecting tags. In this regard, via configuration informationprovided to a configurable monitoring device, the configurablemonitoring device may assume the role of a gate node, such as gate nodes180 located at the doorway 170. The gate nodes may be configured todetect passing EAS tags, such as a conventional EAS tag or aconfigurable monitoring device configured to operate as an EAS tag, andsound an alarm (e.g., an alarm included on the tag, an alarm includedwith the gate node, a storewide alarm). A gate node may directly sound alocal alarm, or the gate node may communicate with the monitoring systemmanager 256 to sound an alarm.

It is noteworthy that, due to the dynamic reconfiguration ability ofconfigurable monitoring devices, any configurable monitoring device maybe configured to operate as a gate node. As such, EAS gates may beimplemented dynamically at many locations within a retail environment.For example, configurable monitoring devices that have been configuredto operate as tags and are affixed to a product on a shelf within theretail environment may also be re-configured to operate as a gate nodefor the aisle where the products are located.

In addition to performing EAS functionality, a monitoring system may beconfigured to perform additional advanced security functionality. Someadvanced security features, as well as a number of other inventory,marketing, and other features may rely upon implementation of an RTLSwithin a monitoring system. To implement RTLS solutions, configurablemonitoring devices may be configured as location nodes.

According to some example embodiments, the beacon signals generated bythe nodes may be used for locating a tag. In this regard, a tag may beconfigured to report to, for example, the monitoring terminal that thetag is currently within the range of a beacon signal provided by aparticular node. The nodes may be configured to randomly, based on analgorithm, modify the beacon signal strength. When the signal strengthis modified, some tags that were in range may no longer be in range, orsome tags that were previously in range may now be within range of thebeacon signal. As tags come in and out of range, due to the changingsignal strength, the signal strength at the time may be used todetermine the distance that a tag is from a particular node. In somecases, if the distance is determined with respect to multiple nodes, aphysical location of the tag can be determined.

According to some example embodiments, standard operating power settings(describing standard fluctuations in power) may be utilized in astandard locating mode. However, in an active locate mode, when thelocation of a specific article is desired, an active locate powersetting may be utilized.

Additionally, or alternatively, a locating node may be configured to usemultilateration, hyperbolic positioning, time difference of arrival(TDOA), trilateration, triangulation, received signal strengthindication (RSSI), global positioning systems (GPS), or other locatingmechanisms to support identifying the location of a tag within a retailenvironment. According to some example embodiments, a locating node mayoperate in isolation to detect the presence, and possibly the strengthof a signal to determine when a tag is nearby. Locating nodes may takesignal measurements and forward the information to, for example, themonitoring system manager 256 to analyze the signal and determine alocation. According to some example embodiments, location nodes may beplaced at strategic locations within the retail environment to supportaccurate locating of tags.

Due to interference that can occur in enclosed environments, such asretail stores, a signal power optimization procedure may be performed bythe monitoring system, for example, directed by the monitoring terminal,to minimize interference and determine optimum signal strength forbeacon signals. In this regard, the signal strength of the various nodesmay be modified to determine settings where minimal interference andnode signal overlap occurs.

To support real-time locating of tags (and the products to which the tagis affixed), tags may be configured to provide locating signals (e.g.,status signals) that may be received, for example, by configurablemonitoring devices configured as locating nodes. Indications of thelocating signals may be provided to the monitoring system manager 256for analysis to determine the location of the tags within the retailenvironment. Upon determining the location of a tag, the monitoringsystem manager 256 may be configured to output the location of the tagon a map displayed via the user interface 258 as shown for example inFIGS. 3 and 5.

In addition to simply outputting the location of the tag to the userinterface 258, the monitoring system manager 256 may be configured toconsider the location information of a tag with respect to definedrules, alarm conditions, and alarm responses. In this regard, zones ofinterest within a retail environment may be defined, and when themonitoring system manager 256 determines that a tag has entered a zoneof interest security functionality, such as an alarm response, may beimplemented. For example, store personnel may wish to define an alarmcondition when products enter the restroom area 150 of FIG. 3. As such,a zone of interest may be defined for the restroom area 150.Accordingly, when the monitoring system manager 256 determines that atag has entered the restroom area, an alarm signal or message may begenerated, and an alarm response may be implemented sounding an alarm.The alarm signal or message may be sent to the tag, and an alarm on thetag may be activated. Additionally or alternatively, a notification maybe provided to store personnel, via for example, a mobile communicationsterminal and/or a remote alarm may be activated. Further, zones ofinterest may be defined with respect a variety of areas within theretail environment (e.g., the stock room, point of sale, fitting room,etc.).

A zone of interest may also be associated with additional parameters,such as a time interval or duration. For example, a customer may bepermitted to bring an article with a tag into the fitting room 130, butonly for a threshold duration of time. Store personnel may, for example,wish to set a thirty minute duration for the fitting room. Accordingly,the monitoring system manager 256 may be configured to define a durationof time, such as thirty minutes, for a zone of interest. The monitoringsystem manager 256 may be configured to implement a timer based on thethreshold duration. The timer may continue to run while the tag islocated within the zone of interest and, when the time reaches thethreshold, an alarm signal or message may be generated and transmittedby the monitoring system manager 256. If the monitoring system manager256 determines that the tag has moved out of the zone of interest, themonitoring system manager 256 may be configured to reset the timer.

Locating a tag may also allow for tracking the movement of a tag and theassociated product through the store. Tracking the movement of theproduct may provide inventory, security, and marketing functionality.With respect to security functionality, it has been determined that manyexperienced shoplifters move about a store in a particular manner. Basedon the location information determined for a tag, the movement of aproduct may be tracked by the monitoring system manager 256 and amovement profile may be generated and compared to suspicious activitymovement profiles. If a match is identified, a notification may beprovided to a manager, security guard, or the like via a mobilecommunications terminal to investigate the situation. Further, accordingto some example embodiments, the monitoring system manager 256 may haveconfigured other tags, or may signal other tags on nearby devices toalarm when a match is identified to, for example, assist in locating theshoplifter. Adjacent tags could provide an alarming pattern that“follows” a would-be shoplifter around or through the retailenvironment.

Additionally, the monitoring system manager 256 may be configured tointerface, via a network connection or the like, with customerinformation terminals 195 to support security functionality. Customerinformation terminals 195 may be computing devices including a displayand audio output capabilities (e.g., speaker, speaker driver, etc.). Acustomer information terminal may be located at strategic securitylocations such as exits and entrances. The monitoring system manager 256may be configured to interface with the customer information terminals195, via for example a network connection, to provide output tocustomers and would-be shoplifters. For example, a customer informationterminal and a movable video camera may be located at the exit of aretail environment. The moveable video camera may be controlled by themonitoring system manager 256. When the monitoring system manager 256determines that a tag has moved into a zone of interest defined near theexit, the movable camera may move to capture the image of the individualcarrying the tag (and the associated product). The video captured by thecamera may be displayed on the customer information terminal to indicateto the shoplifter that they are being recorded and thereby have adeterrent effect.

In a similar application involving customer information terminals, tagsentering a store may be considered. For example, if the monitoringsystem manager 256 determines that a tag has entered the store throughthe front entrance, the monitoring system manager 256 may be configuredto cause the customer information terminal to either visually and/oraudibly direct the customer to the customer service desk for productreturns.

In addition to configurable monitoring devices being configured as EASgate nodes, configurable monitoring devices may also be configured tooperate as gate nodes via the locating functionality described above orbased on a determination that a tag is within range of a gate node'sbeacon signal. In some example embodiments, a gate node may detect theproximity of a tag by receiving communications from the tag in responseto a beacon signal provided by the gate node. To avoid situations wherea gate node detects the proximity of a tag that is properly within theretail environment, and is not located so close to the exit so as toindicate that the attached article is being stolen, guard nodes may beimplemented. The guard nodes may be located near an exit and may beconfigured to prevent tags within the store from improperly associatingthemselves to the gate nodes and causing erroneous alarming.

A gate node may be connected to mains power, and may include a batteryto support operation when mains power is lost. The gate node maytransmit regular beacon signals, which include the gate node's uniqueidentifier, and listen for responses from tags that are within range. Ifa tag detects that the strongest beacon signal that the tag is receivingis from a gate node, the tag may transmit a message including the tag'sunique identifier to the gate node and the tag may enter a first alarmmode. In this regard, a tag may maintain a list of identifiers for gatenodes to determine when a signal is being detected from a gate node.

In the first alarm mode, the tag may be configured to emit an audiblechip every second (or other predetermined time period), providing adeterrent indication to an individual holding the article to which thetag is affixed. While in the first alarm mode, the tag may continue tolisten for beacon signals from other nodes, and if a beacon signal froma non-gate node becomes the strongest beacon signal detected by the tag,the tag may transfer from the first alarm mode to a normal mode (e.g.,since the tag has apparently moved away from the gate node and theexit). However, if the strongest received beacon signal continues to bethe signal from the gate node, and the received signal strength passes apredefined gate node signal strength threshold, the tag may transferinto a second alarm mode. In the second alarm mode, the tag may beconfigured to alarm continuously. Again, the tag may continue to listenfor beacon signals from other nodes, and if a beacon signal from anon-gate node becomes the strongest beacon signal detected by the tag,the tag may transfer from the second alarm mode to the first alarm modeor a normal mode (e.g., since the tag has apparently moved away from thegate node and the exit).

As mentioned above, tag tracking may also provide marketing benefits.Movement of tags associated with particular products may logged by themonitoring system manager 256 over a period time, and the monitoringsystem manager 256 may be configured identify customer trends byaggregating the data. Using the trends, product layout within a storemay be modified to increase sales. The customer trends may revealpurchasing patterns, customer traffic patterns, in-store dead-spots, andthe like, which may not have otherwise been identified. Further,information regarding the effects of moving product display racks andassociated products within the store may be determined based on themovement of customers and the sales of the associated products.

With respect to additional marketing functionality, since the locationof a product can be determined, the monitoring system and the monitoringsystem manager 256 may be configured to make suggestions to customersfor purchasing other products. For example, movement of a tag associatedwith a dress shirt may be detected, and the movement may be tracked to asales area for neck ties. The monitoring system manager 256 may beconfigured to consult a database to suggest a neck tie that matches theshirt, based on attribute information associated with the tag affixed toand associated with the shirt. To implement the suggestion procedure,the monitoring system manager 256 may interface with a customerinformation terminal 195 located near the neck tie retail area.

Example marketing compliance applications and functionality may also beimplemented by the monitoring system. In this regard, some retail storesmay have requirements for how the store should be set (i.e., whereparticular products should be located within the store). A floor plan orset design may be followed for setting the store. To ensure that a storecomplies with a given set design, the location of tags may be queried.Tags associated with particular products may be checked against astored, electronic set design to ensure that the products are located inthe correct locations within the store. For example, the location of thewinter sweaters within the store may be queried, to determine if thewinter sweaters have been located on a table at the entrance of thestore in accordance with a set design. The results of the query may becompared to the set design to determine whether the store complies inthis regard.

Another example marketing application may be automatic pricemodification. In this regard, a tag may be configured to change theprice of a product (or suggest the change of a price for the product)based on various factors. A tag may be configured to implement a timerand determine, for example, a “time on the sales floor” value. If thetime on the sales floor value reaches a threshold level, the price forthe article that the tag is associated with may be modified. To supportthis functionality, according to some example embodiments, when the tagis commissioned or is placed on the sales floor, a time and datethreshold for the article may be defined. For example, a thirty daythreshold may be set. When thirty days has passed, as determined by thetag or the monitoring terminal, the tag may be configured to, or themonitoring terminal may direct the tag to, modify or suggestmodification of the price of the article. Additionally, oralternatively, the tag may alarm when the threshold is reachedindicating to sales personnel that the tag should be moved to theclearance rack. The price may also be modified based on the sales ofrelated products. For example, if sales of a particular product havebeen increasing, the price could be raised.

Another example marketing application may involve a tag being associatedwith, or assigned to, a specific customer (customer tag). In thisregard, the customer tag may be permanently assigned to a customer(e.g., the customer leaves the retail store with the tag), or the tagmay be temporarily assigned to a customer upon visiting the retail store(e.g., the customer returns the tag upon leaving the store). The tagand/or the monitoring system may be configured to store profileinformation about the customer in association with the tag. In thisregard, the customer's profile information may be stored on the tag orat the monitoring terminal. In some example embodiments, the tag may beconfigured to wirelessly interface with a cell phone to retrieve profileinformation. The profile information may include the customer's name,age, gender, home address, phone numbers, credit card numbers, creditinformation, purchasing preferences, and the like.

The profile information may also include information indicative of acustomer loyalty level. In this regard, based on the customer loyaltylevel, various loyalty program features may or may not be available tothe customer. For example, tags associated with a customer having aparticular customer loyalty level may be configured to allow a customerto use the self check out lane at a retail store, open a display casewithout the assistance of store personnel, open a security device thatprotects a product, purchase a product using pre-stored credit cardinformation, de-commission security tags associated with a purchasedproduct, and the like.

The customer tag may also be configured to provide for tracking andpositioning the customer in the store. Further, the customer tag may beconfigured to receive, for example via the monitoring system, a productlist (e.g., a grocery list), and the customer tag may assist thecustomer in locating the products on the list.

According to various example embodiments, a tag, such as a tagconfigured for security functionality, marketing functionality,inventory functionality, or as a key (e.g., a manager's key) may beconfigured to provide for assisting an individual with locating anothertag and the associated product. In this regard, a locator tag, in thepossession of an individual attempting to locate a target tag, may beconfigured to provide a user with an indication of the where the targettag is located or how far the target tag is away from the locator tag.The locating tag and/or the target tag may be configured to provideaudible and/or visual feedback to the user to indicate the location ofthe target tag. For example, the locating tag and/or the target tag maybe configured to output audible beeps or clicks (similar to the sound ofa Geiger counter), the frequency of which may increase as the locatingtag moves closer to the target tag. The output may be based on locatingthat is performed via the beacon nodes described above, or via signalstrength detection directly between the locating tag and the target tag.

As mentioned above, tag location assistance functionality, such as theGeiger counter-type functionality described above may be implemented ina number of applications. In another example, a locator tag, such as atag configured as a manager's key, may be used to locate tags that havereached a threshold battery charge level. A tag with a low batterylevel, where the tag includes battery monitoring circuitry (e.g., via aprocessor) may be configured to alarm to indicate the low batterycondition. Additionally, a tag with low battery level may be configuredto provide a wireless signal indicating the low battery condition. Thewireless signal may be detected by the locator tag and the locator tagmay be configured to provide an indication of the location of the lowbattery level to a user of the locator tag. According to some exampleembodiments, tags near a low battery level tag may be configured torelay the low battery level indication via a wireless signal toneighboring tags, and the neighboring tags may report the low batterypower condition to provide for locating the low battery level tag, evenafter the low battery level tag can no longer communicate.

With respect to inventory applications, the monitoring system manager256 may be configured to track inventory generally, as well as track thelocation of inventory via tags. The monitoring system manager 256 may beconfigured to track inventory by monitoring and logging status signalsprovided by the tags, in addition to commissioning and decommissioningactivities.

The monitoring system manager 256 may also assist in locating particularinventory to, for example, assist in a sale. The monitoring systemmanager 256 may be configured to receive requests for a particularproduct (e.g., brown slacks, waist size 32, in-seam length 30) andcommunicate with tags that meet the criteria of the request to cause thetags to alarm. An alarm in this regard, may be a subtle, soft audioalarm that would assist a sales person and a customer in locating thedesired product.

Another example inventory application may involve the monitoringsystem's interaction with totes. A tote may be a shipping container,such as a plastic shipping container, that can hold smaller, and oftenhigher value, products, such as pharmaceuticals, makeup, batteries,film, jewelry, and the like. Totes may be loaded at a warehouse, oranother store, and shipped to a destination store. A tote may include amechanical locking mechanism that requires, for example, a magnetic keyor mechanical interaction with a key, to open the tote and access theproducts inside the tote. In some example embodiments, a tote may alsoinclude a configurable monitoring device configured as a tote tag.

A tote tag may be used for locating the tote, similar to the mannersdescribed above. A tote tag may also be configured to detect thepresence of tags, and associated products within the tote. In thismanner, a tote tag may operate similar to a node, with respect to thetags stored within the tote. In some embodiments, the tote tag maymaintain an inventory of the products within the tote by virtue ofcommunication with each respective tagged product in the tote and theextraction and/or storage of product related information associated witheach respective tag. As the tote moves from the warehouse to adestination store, the inventory information may be verified at bothlocations to ensure that the contents of the tote have not been tamperedwith or stolen.

The tote tag may also interface with a key, such as a manager's key. Inthis regard, the key may be enabled to deactivate security functionalityof the tote tag, such as alarming. The tote tag may be configured toalarm if an attempt is made to open the tote without the key or with anunapproved key. The tote tag may also alarm if communication is lostwith the tag of one or more of the tagged products within the tote. Akey may be configured to interface with the tote tag, either directly orthrough the monitoring system, to deactivate, or activate, the totetag's alarming functionality. The monitoring system, or the tote tag maybe configured to manage access to the contents of the tote by, forexample, maintaining a list identifying the particular keys or the typesof keys (e.g., high level manager's key) that have been enabled to openthe tote. In the event that an unapproved key is used, or is attemptedto be used, for opening a tote, the tote tag may alarm.

Based on the forgoing, FIG. 4 illustrates an example method for managingconfigurable monitoring devices in accordance with various exampleembodiments of the present invention that may be implemented by themonitoring system manager 256. At 400, configuration information for aconfigurable monitoring device may be generated that defines a role forthe target configurable monitoring device. Specific parameters such asrules, alarming conditions, alarming responses, attribute information,and the like may be defined and included in the configurationinformation. At 410, the configuration information may be provided to atarget configurable monitoring device via, for example, a wirelessnetwork connection. The target configurable monitoring device mayreceive and store the configuration information and subsequently operatewithin the role defined by the configuration information. If theconfiguration information defines the role of a node or a gateway,role-based communications may be received from, and transmitted to, thenode or gateway during the operation of the configurable monitoringdevice as a node or gateway.

If the configuration information defines the role of a tag, a commissionsignal may subsequently be provided to commission the tag at 430.Subsequently, role-based communications may be received from, andtransmitted to, the tag at 2440 during the operation of the configurablemonitoring device as a tag. The tag may later be provided a decommissionsignal to decommission the tag 450. Once decommissioned, the tag mayawait re-commissioning at 430 by providing another commission signal.

FIGS. 5A-8 illustrate example windows for displaying aspects of a userinterface that may be implemented on a monitoring terminal. FIGS. 5A,Billustrate an example window 500 displaying a rendered representation ofa monitoring system. The tag map 510 illustrates an example sales floorfor a retail environment. The tag map 510 includes location-basedrepresentations of nodes (referred to as “hubs”) that are positioned atvarious locations throughout the sales floor. The nodes are uniquelyidentified by a label (e.g., “Hub 14”) followed by an associated tagcount in parentheses, indicating the number of nearby tags (or tagswithin range of the signals (e.g., beacon signals) being provided by thenodes. When the monitoring terminal determines, based on communicationsfrom the tags or the nodes, that a tag has moved, such that the tag isdisassociated with a first node and newly associated with a second node,the tag count may be decremented at first node and incremented at thesecond node. The tag map 510 also depicts POS nodes (e.g., “Pos2”, “Pos3”, etc.). Near the entry area a gate node, “Gate1”, is depicted whichis configured to protect the entry/exit area. The tag map 510 alsoincludes a gateway node, “Root0” configured to interface with anexternal network, to which the monitoring terminal may be connected.

The example window 500 also includes a tag tree 520. The tag tree 520includes a listing of the nodes that are members of the monitoringsystem. A node that has tags within range, such as Hub16, may beexpanded to display entries for each tag that is currently within rangeof, or otherwise associated with the node. As tags move form node tonode, the tag tree 520 may be updated to show the current associationsbetween the tags and the nodes. The tag tree 520 also includes a statuslegend 511 for describing the status of the tags or nodes. In thisregard, the monitoring terminal may be configured to highlight, forexample, an alarming tag red, an unresponsive tag purple, and a lowbattery tag yellow, or some other color/highlighting scheme may beemployed.

The example window 510 also includes an event log 530. The informationdepicted in the event log may be linked to the currently selected itemin the tag tree 520. As such, event information for the selected tag maybe displayed. A time stamp may be associated with each event. Exampleevents may include tag movement between node events, alarm events,failed communications events, tamper events, low battery events, etc.

FIG. 6 illustrates an example tag information window 600 for attributeinformation associated with a tag or node. The example tag informationwindow 600 depicts attribute information for a tag. An image 610 of anarticle to which the associated tag is affixed may be provided in theexample tag information window 600. Further, additional attributeinformation may be provided in the tabular area 620, such as the tagaddress, the current battery level, the currently associated hub, adescription of the affixed article, a stock-keeping unit (SKU) value,the time/date of the last report from the tag, the time/date of the lasttransition between nodes for the tag, the time/date of the lastcommission of the tag, the time/date of the last decommission of thetag, and the like.

FIG. 7 illustrates an example hub information window 700. The hubinformation window 700 may include a tabular area 710 that includesinformation about the hub (or node). Example hub attribute informationmay include the hub address, the hub label or description, the batterylevel for the hub, the current number of associated tags, the date/timethat the hub last reported, for example, to the monitoring terminal, andthe like.

FIG. 8 illustrates an example battery level window 800 for a tag. Thebattery level window may include a graphical representation of the pastand current battery level on a line graph. The graph may be providedwith respect to voltage on the y-axis, and time on the x-axis. Athreshold battery level 830 may also be included on the graph, which mayindicate the battery level that would place the tag in a low batterystatus.

Many of applications and functionality described herein utilize wirelesscommunications between the monitoring terminal 62 and the configurablemonitoring devices. In addition to, or in lieu of, communicating withindividual tags via this air interface, the communications interface 252of the monitoring terminal 62 may communicate with a separate bridgedevice to forward and receive information and data to and fromconfigurable monitoring devices. The bridge device may operateunilaterally or in conjunction with the monitoring terminal 62 to manageconfigurable monitoring devices. The bridge device, which may be ahand-held scanner-type device, can be configured to operate in one oftwo communication modes to interface with tags affixed to retailproducts for security, inventory, and other purposes. In a firstcommunication mode, the bridge device is configured to communicate withtags that are configured for RFID type communications. For example, thetags and the bridge device may be configured to communicate inaccordance with the Generation II Ultra High Frequency (UHF) RFIDstandards. In a second communication mode, the bridge device isconfigured to communicate with tags using a protocol built on the IEEE802.15.4 standard, such as ZigBee or a proprietary protocol built onIEEE 802.15.4. To support the dual modes of communication, the bridgedevice may include a transmitter/receiver and an antenna configured tosupport IEEE 802.15.4, as well as, a modulator/demodulator, and possiblya separate antenna, to support RFID communications. According to someexample embodiments, the bridge device may include a configurablemonitoring device configured to operate a bridge device. Via seamlesstransition between the two communications modes, a single, possiblyhand-held, bridge device can operate as a tag reader, and may be used tocommunicate with disparate types of tags. Communications with the tagsmay be performed for a variety of reasons, such as for countinginventory, price checking, tag firmware upgrades, tag encoding, and thelike.

Referring now to FIG. 14, there is shown an embodiment of a beamformingcalibration system according to the invention suitable for use in aconfigurable monitoring system. The beamforming calibration system ofthe present invention is useful for enhancing read range and reliabilityin RFID applications, and facilitates deployment of RFID applications bynon-experts. A distributed architecture uses techniques for antennabeamforming and a feedback control loop to direct radio frequency (RF)energy onto a specific region, referred to as an interrogation zone,which includes a configurable monitoring device configured as acalibration node where one or more RFID tags may be located. It will beunderstood that any of the devices in the beamforming calibration systemcan be configurable monitoring devices.

The use of a beamforming system increases the signal strength in theinterrogation zone for a given transmitted power, thus allowing foreither increased range for a given amount of transmitted power, or forreduction in the transmitted power required to achieve a given signalstrength in the interrogation zone. As a result, interference (e.g.,inter-reader interference) can be reduced in applications where multipleRFID readers are deployed. The beamforming system also directs thetransmitted signal and hence reduces the multi-path interference due tosignal reflection from scattering, thus reducing signal fading andincreasing reliability.

A feedback control loop using a configurable monitoring deviceconfigured as calibration node in the interrogation zone enables thebeamforming system to automatically optimize the signal power andsignal-to-noise ratio in the interrogation zone without manualconfiguration and/or tuning. The beamforming system, comprisingbeamforming nodes, calibration nodes, and a reader node, canself-calibrate to adjust for the environmental conditions and therelative positions of the nodes and the interrogation zone. Thus, theinstallation and maintenance of the beamforming system is simplified.

The beamforming system eliminates the need for connecting thebeamforming nodes via coaxial cables, decreasing cost and increasing theflexibility of deployment. The flexibility in placement of thebeamforming nodes also reduces fading and shadowing effects. Forexample, even if the path from one of the beamforming nodes to the RFIDtags is blocked, the signal from the other beamforming nodes may provideenough received signal strength at the RFID tag for reliable operationand for communication with the reader.

Various embodiments of the invention include a system for radiofrequency identification of a tagged item in an interrogation zonecomprising configurable monitoring devices configured as a plurality ofbeamforming nodes, each configured to generate radio frequencyidentification signals in a first frequency band, at least onecalibration node disposed in the interrogation zone configured tomeasure a signal strength of the radio frequency identification signalsand to transmit a signal strength data in a second frequency band, and areader node configured to receive the signal strength data in the secondfrequency band, adjust the radio frequency identification signalsgenerated by the beamforming nodes, and receive a radio frequencyidentification data in the first frequency band from the tag.

Other embodiments of the invention include a method for beamformingcomprising generating radio frequency identification signals, measuringa signal strength of the radio frequency identification signals in aninterrogation zone, reading the signal strength, and adjusting the radiofrequency identification signals based on the signal strength in afeedback control loop.

Still further embodiments of the invention include a method forbeamforming comprising sending a command and power and/or phase data toa plurality of beamforming nodes, transmitting a radio frequencyidentification signal using the plurality of beamforming nodes,receiving the radio frequency identification signal using a calibrationnode, transmitting a signal strength data based on the radio frequencyidentification signal from the calibration node to the reader node,adjusting the command and the data based on the signal strength data,and sending the adjusted command and the adjusted data to the pluralityof beamforming nodes.

The present invention includes systems and methods for beamforming inradio frequency identification applications. A distributed architectureof configurable monitoring devices uses techniques for antennabeamforming and a feedback control loop to direct radio frequency (RF)energy onto a specific region including a calibration node, referred toas an interrogation zone, where one or more RFID tags may be located.

The distributed architecture of the beamforming system is resistant tofading and shadowing effects, providing accurate RFID reader operationeven in environments with multi-path reflections or environmentalchanges, such as people moving around, changes in the location ofequipment, etc. By connecting the beamforming nodes to the RFID readernode using a wireless coupling, the need for coaxial cable iseliminated. The distributed architecture also enables the use oflow-cost, low-data rate wires for communication between the reader nodeand the beamforming nodes. Furthermore, the architecture of thebeamforming system provides flexibility in the number and the placementof the beamforming nodes.

The beamforming system is self-calibrating, eliminating the need formanual configuration of the RFID reader and antennas when the system isinitially set up. In addition, the self-calibration feature enables thebeamforming system to function when the radio frequency identificationtags are in motion. The self-calibration feature is enabled by the useof a feedback control loop, using feedback from a calibration nodeplaced in the vicinity of the tags (i.e., in the interrogation zone). Invarious embodiments, the beamforming nodes use the closed-loop feedbackfrom one or more of the calibration nodes to adapt the phase of theradio frequency identification signal transmitted by the beamformingnodes, so as to maximize the power or the signal-to-noise ratio receivedby the RFID tags in the interrogation zone.

The feedback control loop provides flexibility in the positioning of thebeamforming nodes. Thus, positioning of the beamforming nodes can bedone based on a combination of practical considerations, such as ease ofdeployment, and performance considerations, such as maximization ofpower or signal-to-noise ratio. The closed-loop feedback is providedusing a calibration node in the interrogation zone.

The closed-loop feedback adaptation of the powers and/or phases of theradio frequency identification signal transmitted by the beamformingnodes can be achieved by various iterative algorithms, includingalgorithms that require only one bit of feedback per iteration, see,e.g., Bernard Widrow and John M. McCool, “A Comparison of AdaptiveAlgorithms Based on the Methods of Steepest Descent and Random Search,”IEEE Transactions on Antennas and Propagation, vol. 24, no. 5, pp.615-637 (September 1976), and R. Mudumbai, J. Hespanha, U. Madhow, G.Barriac, “Scalable Feedback Control for Distributed Beamforming inSensor Networks,” Proc. 2005 IEEE International Symposium on InformationTheory (ISIT 2005), Adelaide, Australia (September 2005).

In various embodiments, the configurable beamforming system can use the900 MHz UHF frequency band for radio frequency identification signalsfor a first frequency band (the RFID band) employed by the signalsreceived and transmitted by the RFID tag, and another band, for examplethe 2.4 GHz band, as a second frequency band for control signals tocouple between the calibration node, the reader node, and beamformingnodes. The separation in frequency between the RFID band and the controlband simplifies the design of the analog components of the beamformingsystem. The beamforming system may use frequency bands other than thoseidentified herein for the first frequency band and the second frequencyband. Furthermore, the RFID band and the second frequency band forcontrol signals may partially or fully overlap in frequency.

With reference to FIG. 14, there is shown a configurable monitoringdevice beamforming system for a radio frequency identificationapplication. The system comprises a beamforming module 1110 having twoor more beamforming nodes which generate a radio frequencyidentification signal 1160, a reader module 1120, one or more RFID tags1150, one or more calibration modules 1140, and an interrogation zone1170 in which one or more calibration modules 1140 and RFID tags 1150may be present. A control radio frequency connection 1135 couples thereader module 1120 and beamforming module 1110. A calibration data radiofrequency connection 1180 couples the calibration module(s) 1140 to thereader module 1120, and a radio frequency identification data 1190couples the RFID tags 1150 to the reader module 1120.

In various embodiments, the reader module 1120 may communicate with thebeamforming module 1110 via beamforming control radio frequencyconnection 1135, via beamforming control hardwired connection 1130, orvia both. The calibration module 1140 may also communicate with thereader module 1120 through a hardwired connection (not shown) ratherthan a calibration data radio frequency connection 1180, and directlywith the beamforming module 1110 through either a wireless or ahardwired connection (not shown), rather than indirectly using readermodule 1120. The calibration module 1140 may receive the radio frequencyidentification data 1190 transmitted by the RFID tags 1150 andcommunicate this data to the reader module 1120.

The calibration module 1140 measures the net received signal from thebeamforming module 1110 via the radio frequency identification signal1160. The calibration module 1140 communicates with the reader module1120 (or directly with the beamforming module 1110 as above) to reportthe measurements of the received signal.

A feedback control loop comprising the calibration module 1140, thereader module 1120, and the beamforming module 1110 is used to adjustthe power and phase of the radio frequency identification signal 1160 soas to increase the strength and/or signal-to-noise ratio of the radiofrequency identification signal 1160 received at the calibration module1140. The radio frequency identification signal 1160 transmitted by thebeamforming module 1110 is in accordance with standard RFID reader-tagprotocols, and the response from the RFID tags 1150 is processed in astandard manner by the reader module 1120. The reader module 1120 can beco-located with the beamforming module 1110. In various embodiments, thebeamforming module 1110 is separated from the calibration module 1140 byone meter or more and/or the reader module 1120 is separated from thecalibration module 1140 by one meter or more. In typical applications,these separation distances may vary from less than one meter to morethan one meter.

FIG. 15 is a block diagram of a configurable monitoring devicebeamforming system for a radio frequency identification application. Thebeamforming system 1200 comprises the reader node 1220, a plurality ofbeamforming nodes 1210, a plurality of beamforming control channelantennas 1250, RFID channel antennas 1260, beamforming control hardwiredconnections 1130, beamforming control radio frequency connections 1135,one or more calibration nodes 1230, one or more RFID tags 1150 locatedin the interrogation zone 1170, the calibration data radio frequencyconnection 1180, the radio frequency identification data 1190, and theradio frequency identification signal 1160. The reader node 1220 may usethe standard read/write protocols (e.g., governing the timing ofacknowledgements, retransmissions, multiple-access arbitration) of aconventional RFID reader.

Beamforming nodes 1210 are coupled to two types of radio frequencyantennas, beamforming control channel antennas 1250 and RFID channelantennas 1260. The RFID channel antennas 1260 are used by thebeamforming nodes 1210 to form the radio frequency identification signal1160 to energize and transmit data to the RFID tags 1150 in theinterrogation zone 1170 using a first frequency band, such as thefrequency band for standard RFID communication, herein termed the RFIDband. The beamforming control channel antenna 1250 communicates with thereader node 1220 using a second frequency band, herein termed thecontrol band. In some embodiments, the RFID band may be within the 900MHz UHF radio frequency band and the control band may be within the 2.4GHz unlicensed radio frequency band. The beamforming nodes 1210 generatethe radio frequency identification signals 1160 with appropriate power,phase, and modulated data. They generate the signals 1160 according tothe commands and data provided to the beamforming nodes 1210 by thereader node 1220, through either the beamforming control hardwiredconnection 1130 or the beamforming control radio frequency connection1135.

The beamforming control channel antennas 1250 function in conjunctionwith each other to direct the radio frequency identification signals1160 to the interrogation zone 1170. The calibration node 1230 takesmeasurements of the radio frequency identification signals 1160, such asnet received power or signal-to-noise ratio, and relays feedbackregarding this information back to the beamforming nodes 1210, eitherdirectly or through the reader node 1220 as above. A feedback controlloop is employed by the beamforming nodes 1210 to adapt the phasesand/or transmitted power of the radio frequency identification signals1160 to maximize the power or signal-to-noise ratio received by thecalibration node 1230, and hence any RFID tag circuitry 1240 in theinterrogation zone 1170.

In various embodiments, the configurable monitoring device beamformingsystem 1200 may use any of a number of feedback control loop iterativealgorithms. The feedback control loop maximizes the quality of the netreceived signal at the calibration node 1230, which may be determined bythe net received power or the signal-to-noise ratio. The feedbackcontrol loop may provide a direct estimate of the average received powerat the calibration node 1230, and/or an estimate of both the power andphase evolution of the received signal. Alternatively, the feedbackcontrol loop may provide an estimate of the difference in receivedpowers corresponding to different phase settings employed by thebeamforming nodes 1210. The feedback control loop can be employed foradaptation of a centralized antenna array. Thus, any algorithm that isused in such a centralized setting can be employed in a distributedsetting as well, as long as the beamforming weight w_(i) for the itharray element depends only on its prior values and on the feedback. Inthis case, the ith beamforming node 1210 becomes equivalent to the itharray element in a centralized adaptive antenna array.

One application of the algorithm described in Mudumbai et al. to thebeamforming system 1200 is as follows. The beamforming nodes 1210transmit at constant gain, and vary only their phases. Thus, thebeamforming weight for the ith beamforming node 1210 is w_(i)=e^(jφi).The iterative algorithm then performs the following steps. First, thereader node 1220 commands the beamforming nodes 1210 to randomly perturbtheir phases by a small random number, whose distribution is symmetricaround zero. For example, the perturbation may be chosen with equalprobability to be +a or −a, where a is a small phase value. Alternately,the perturbation may be chosen to be uniform over the interval [−a, a].Next, the calibration node 1230 computes the received power P. Thisvalue is transmitted back to the reader node 1220. In some embodiments,a single bit, denoting whether the present value of P is larger orsmaller than the value at the previous iteration, may be transmittedback to the reader node 1220. If the received power P is larger than theprevious iteration, the phase changes made at the beamforming nodes 1210are kept. Otherwise the phases from the previous iteration are kept.These steps may be repeated. Using this algorithm, the radio frequencyidentification signal 1160 generated by the beamforming nodes 1210 willconverge to the optimal phase values, thus maximizing the received powerat the RFID tags 1150 in the interrogation zone 1170.

When the received power P is reported to the reader node 1220 in afeedback loop control, an iterative algorithm such as a gradient ascentalgorithm may also be used to maximize the received power at thecalibration node 1230. For example, in the ascent algorithms such as theDRD and LRS algorithms in Widrow and McCool, the ith beamforming weightw_(i) depends only on its past value and the feedback. These gradientascent algorithms can therefore be employed for adaptation of thebeamforming weights, even though the beamforming nodes 1210 may not becollocated.

An advantage of the feedback control loop is a reduced need for carefulmanual alignment of the RFID channel antennas 1260. In variousembodiments, the beamforming nodes 1210 use iterative algorithms takingas input the measured data provided by calibration nodes 1230 tooptimize radio frequency identification signals 1160, thus maximizingthe signal quality received at the calibration node 1230. Alternatively,reader nodes 1220 compute and provide commands to the beamforming nodes1210 to optimize the radio frequency identification signals 1160, thusmaximizing the signal quality received at the calibration node 1230. Invarious embodiments, an iterative adaptive algorithm may be implementedin software, firmware, hardware, or a combination to implement thefeedback control loop.

The use of multiple antenna elements (for example multiple RFID channelantennas 1260) for improvements in link power budget, diversity, andspatial multiplexing can be combined with other techniques known tothose of skill in the art of antenna design and/or wirelesscommunications, in various embodiments. For example, instead of thebeamforming nodes 1210 locking onto a reference frequency signal fromthe reader node 1220, their local oscillators can operate in open loop.The frequency offset of the radio frequency identification signal 1160at each beamforming node 1210 from its nominal value can be correctedusing feedback from the calibration node 1230. For example, thecalibration node 1230 can use its local oscillator as a reference tocompute the estimated frequency offset for the ith instance ofbeamforming node 1210, and feed that information back to the ithinstance of beamforming node 1210. This calibration can be done one at atime for each beamforming node 1210. Each beamforming node 1210 can thenapply an appropriate frequency offset correction in transmit circuitryas will be described with reference to FIG. 18. The residual phase driftcan be corrected using the feedback control algorithm. Alternatively, ifthe local oscillator tolerances of the beamforming node 1210 are smallenough, then the frequency drift can be corrected as part of thefeedback control algorithm, without requiring any initial calibrationwhen the beamforming system is set up.

FIG. 16 is a block diagram of a configurable monitoring device readernode 1220. The reader node 1220 comprises a network interface 1310, aprocessor 1320, a beamforming node interface 1330, a calibration nodeinterface 1340, and RFID receiver circuitry 1350. The reader node 1220couples to the beamforming control channel antenna 1250 and the RFIDchannel antenna 1260. The RFID receiver circuitry 1350 receives themodulated and backscattered radio frequency identification data 1190returning from the RFID tag 1150 using the RFID channel antenna 1260,demodulates the data, and provides the data to the processor 1320. Thenetwork interface 1310 enables communication between the reader node1220 and external computing and communication devices (not shown), andmay be implemented using any wired or wireless communication channel.The network interface 1310 may connect with the processor 1320 forcommunication and control between these external computing andcommunication devices and the beamforming system 1200, and may shareRFID tag data from the processor 1320 with these external computing andcommunication devices. This RFID tag data comprises the identity, numberand/or location of the RFID tags 1150 within an interrogation zone 1170.The processor 1320 contains the standard RFID signal decoding algorithmsknown to those of skill in the art of RFID systems that are used toprocess the data received by the RFID receiver circuitry 1350 throughthe RFID channel antenna 1260.

The processor 1320 connects to the beamforming nodes 1210 through thebeamforming node interface 1330 to control the beamforming operations.The beamforming operations comprise specifying which region is to bescanned and specifying the data that is to be sent to the RFID tags1150. The beamforming node interface 1330 may communicate with thebeamforming nodes 1210 through a beamforming control hardwiredconnection 1130 and/or a beamforming control radio frequency connection1135 utilizing a beamforming control channel antenna 1250.

The data received by the processor 1320, through the calibration nodeinterface 1340, controls the algorithm used to direct the radiofrequency identification signal 1160 generated by the beamforming module1110 within the interrogation zone 1170. The calibration node interface1340 may communicate with the calibration nodes 1230 through a hardwiredconnection (not shown), a calibration data radio frequency connection1180 using a beamforming control channel antenna 1250, or both. If thecalibration node 1230 communicates directly with the beamforming nodes1210 rather than with the reader node 1220, as above, the reader node1220 need not contain the calibration node interface 1340.

FIG. 17 is a block diagram of a configurable monitoring beamformingcontrol system. The beamforming control system comprises the reader node1220 and a plurality of beamforming nodes 1210. The reader node 1220 cancommunicate with the beamforming nodes 1210 through three logical linkswhich may be communicated through one or more hardwired or wirelessconnections, as described with reference to FIG. 15. These logical linksare the command link 1451, the data link 1452, and the clock link 1453.The reader node 1220 comprises a calibration feedback processor 1410, anRFID channel demodulator 1420, a carrier generator 1430, and a clockgenerator 1440. The beamforming node 1210 comprises a command interface1460, a modulator 1470, a phase/gain control 1490, and a carriergenerator 1480. The reader node 1220 couples to RFID channel antenna1260 and a beamforming control channel antenna 1250. Reader node 1220uses an RFID protocol 1425 to send data to modulator 1470. Beamformingnode 1210 uses a phase update algorithm 1465 to adjust the phase/gaincontrol 1490.

The reader node 1220 receives feedback information from the calibrationnodes 1230 through the beamforming control channel antenna 1250. Theinformation is demodulated and processed by the calibration feedbackprocessor 1410, and using command link 1451, is distributed to thebeamforming nodes 1210. In some embodiments, the calibration feedbackprocessor 1410 simply passes the data received by the calibration nodes1230 to the beamforming nodes 1210 via the command link 1451. In otherembodiments, the calibration feedback processor 1410 processes the datareceived from the calibration nodes 1230 using an algorithm to generatespecific commands for the beamforming nodes 1210 to control the phaseand/or gain of the radio frequency identification signal 1160transmitted using RFID channel antenna 1260. The reader node 1220generates a clock signal using the clock generator 1440 which is thenused to generate a carrier frequency using the carrier generator 1430.The reader node also distributes the clock signal from the clockgenerator 1440 to the beamforming nodes 1210 over the clock link 1453.This clock signal is used by the beamforming nodes 1210 to achievefrequency synchronization among all beamforming nodes 1210. The carriergenerator 1430 is used by the RFID channel demodulator 1420 todemodulate the data from the RFID tags 1150 within the interrogationzone 1170. The RFID protocol 1425 is used by the reader node 1220 todistribute RFID tag-specific data to the beamforming nodes 1210 over thedata link 1452. This RFID tag-specific data is transmitted to the RFIDtags 1150 within the interrogation zone 1170.

The beamforming node 1210 interfaces with the reader node 1220 throughthe command link 1451, the data link 1452, and the clock link 1453. Theclock link 1453 is used by the carrier generator 1480 to achievefrequency synchronization with the other beamforming nodes 1210. Thedata link 1452 can contain the RFID tag-specific data to be transmittedby the beamforming nodes 1210 over the RFID channel antenna 1260. TheRFID tag-specific data is modulated onto a carrier at the RFID linkfrequency in the RFID band (the first frequency band) using a modulator1470. The modulated carrier's phase and power level are set by thephase/gain control 1490 and subsequently transmitted through the RFIDchannel antenna 1260. Using command link 1451, the command interface1460 receives information from the reader node 1220 regarding thereceived radio frequency identification signal 1160 at the calibrationnode 1230. The beamforming node 1210 uses this information, using thephase update algorithm 1465, to control the gain and phase of thecomplex envelope of radio frequency identification signal 1160transmitted over RFID channel antenna 1260. The gain g and phase φtogether define a complex-valued beamforming weight w_(i)=ge^(jφ), wherej=√−1.

FIG. 18 is a block diagram of a configurable monitoring devicebeamforming node system. The beamforming node 1210 comprises a readercontrol interface 1510, a processor 1520, and transmit circuitry 1530.The beamforming node 1210 is coupled to the beamforming control channelantenna 1250. The beamforming node 1210 is also coupled to an RFIDchannel antenna 1260. The reader control interface 1510 receives thedata and the commands sent over the command link 1451 and data link 1452from the reader node 1220. As above, the beamforming node 1210 mayinterface with the reader node 1220 via a beamforming control channelantenna 1250, a beamforming control hardwired connection 1130, or acombination thereof. The processor 1520 utilizes the data and commandsprovided by the reader control interface 1510, along with the clock link1453 from the reader node 1220, to generate the radio frequencyidentification signal 1160 using the transmit circuitry 1530 which thendrives RFID channel antenna 1260 to transmit the radio frequencyidentification signal 1160.

FIG. 19 illustrates a block diagram of a configurable monitoring devicecalibration node system, according to various embodiments. Thecalibration node 1230 comprises RFID channel receive circuitry 1610,address decoder circuitry 1620, feedback channel computation circuitry1630, and feedback channel transmit circuitry 1640. The calibration nodeis coupled to an RFID channel antenna 1260 and a beamforming controlchannel antenna 1250. As above, in some embodiments, the calibrationnode 1230 may connect directly to either the reader node 1220 or thebeamforming node 1210 via a hardwired connection (not shown). ThroughRFID channel antenna 1260, the calibration node 1230 receives anddemodulates the radio frequency identification signal 1160 using RFIDchannel receive circuitry 1610. The feedback channel computationcircuitry 1630 then analyzes the received signal for use in the feedbackloop to control the radio frequency identification signal 1160 generatedby the beamforming nodes 1210. The analysis depends on the specificbeamforming algorithm implemented in the beamforming control system1200. The resulting data may include signal-to-noise ratio, receivedsignal strength, and complex amplitudes. The data is quantized to therequired number of bits by the feedback channel computation circuitry1630 and transmitted back to the reader node 1220 using the feedbackchannel transmit circuitry 1640.

In a typical system, one or more calibration nodes 1230 may bepositioned in the interrogation zone 1170. The reader node 1220 mayselect feedback information from any or all of the calibration nodes1230. In addition, the reader node 1220 synchronizes the calibrationnodes 1230 so that they do not send data at the same time in a way thatcauses interference. To accomplish this, in various embodiments eachcalibration node 1230 within the beamforming system 1200 has a uniqueaddress. In these embodiments, the reader node 1220 first transmits theaddress of the calibration node 1230 that should respond. Thistransmission may be accomplished via the beamforming nodes 1210 usingthe radio frequency identification signal 1160. Each calibration node1230 receives this address information using the RFID channel antenna1260. After demodulation by the RFID channel receive circuitry 1610, thereceived address is decoded and compared to the predeterminedcalibration node address by the address decoder circuitry 1620. Eachcalibration node 1230 only responds to the reader node 1220 if thereceived address matches its predetermined address.

FIG. 20 illustrates a beamforming panel array, according to variousembodiments. The beamforming array 1700 consists of a plurality ofbeamforming panels 1710, each of which includes a plurality ofbeamforming nodes 1210 and their respective beamforming control channelantennas 1250 and RFID channel antennas 1260 (not shown). A beamformingarray 1700 may include any number of beamforming nodes 1210 on abeamforming panel 1710, and may include any number of beamforming panels1710, as long as there are at least two beamforming nodes 1210 in thebeamforming array 1700. Any number of the beamforming panels 1710 can beconfigurable monitoring devices. To improve the beamsteeringcapabilities for the radio frequency identification signal 1160, thebeamforming array 1700 may be arranged such that the distance betweenall beamforming nodes 1210 is equal to a distance 1720, where distance1720 is optimally one half the wavelength of the radio frequencyidentification signal 1160 transmitted by the beamforming array 1700. Invarious embodiments, the beamforming array 1700 may extend into one, twoor three spatial dimensions.

To reduce interference and increase read range and reliability, morebeamforming panels 1710 may be used in the beamforming array 1700 toproduce a radio frequency identification signal 1160 directed to anarrower region of space. In other embodiments, however, the beamformingnodes 1210 may be arbitrarily arranged without a uniform distancebetween each of the beamforming nodes 1210. The feedback control loopdescribed herein enables automated self-calibration, which may be usedto compensate for an unknown arrangement of a set of beamforming nodes1210 in a beamforming panel 1710 and/or an arbitrarily arranged set ofbeamforming panels 1710 in the beamforming array 1700.

FIG. 21 is a flowchart of a method of beamforming, according to variousembodiments of the present invention. A feedback control loop is used tocontrol a directional electromagnetic energy beam that energizes andcommunicates with the RFID tags 1140, 1150 within the interrogation zone1170. In step 1810, the radio frequency identification signal 1160 isgenerated in a first frequency band. In step 1820, the calibration node1230 takes measurements of the received radio frequency identificationsignal 1160, such as average power and/or signal-to-noise ratio. In step1830, the calibration node 1230 transmits the signal measurement datameasured in step 1820 to either the reader node 1220, to the beamformingnodes 1210, or both. In step 1840, the phase and/or power level of theradio frequency identification signal 1160, transmitted by for examplethe beamforming nodes 1210 and/or the RFID channel antenna 1260, and isadjusted based on the signal measurement data using a feedback loop. Thefeedback loop may use one of a variety of algorithms for beamforming asdiscussed above. Following step 1840, the method returns to step 1810and may repeat.

FIG. 22 is a flowchart of a method of reading data from RFID tags,according to various embodiments of the present invention. In thismethod, data from the RFID tag circuitry 1240 is read by the reader node1220, which then determines the location of specific RFID tags 1150based on, for example, the beamsteering features of a beamforming array1700. In step 1910, the reader node 1220 receives data transmitted bythe RFID tag circuitry 1240 via the modulated and backscattered radiofrequency identification data 1190. In step 1920, the reader node usesinformation received from the RFID tag circuitry 1240, including forexample an identification number, along with the data from thecalibration node 1230 and data from the beamforming control algorithm todetermine the physical location of RFID tag circuitry 1240, andconsequently the item tagged by RFID tag circuitry 1240. In variousembodiments, the location of an RFID tag 1150 may be determined usingthe signal strength of the radio frequency identification data 1190 as afunction of the radio frequency identification signal 1160 received byan RFID tag 1150 and the one or more calibration nodes 1230.

FIG. 23 illustrates the methods of beamforming, according to variousembodiments of the present invention. In these methods, a feedbackcontrol loop is utilized to control a directional electromagnetic energybeam that energizes and communicates with the RFID tags 1150 within theinterrogation zone 1170. In step 2010, the reader node 1220 sends acommand and data to the beamforming nodes 1210 to control the generationof the radio frequency identification signal 1160. In step 2020, thebeamforming nodes 1210 transmit a radio frequency identification signal1160 directed toward the interrogation zone 1170. In step 2030, thecalibration nodes 1230 receive the radio frequency identification signal1160 transmitted by the beamforming nodes 1210. In step 2040, thecalibration node 1230 transmits a signal strength data, based onmeasurements of the radio frequency identification signal 1160, to thereader node 1220. In step 2050, the reader node 1220 adjusts the commandand data to be sent to the beamforming nodes 1210 based on the signalstrength data. In step 2060, the reader node 1220 sends the adjustedcommand and data to the plurality of beamforming nodes 1210. Followingstep 2060, the method returns to step 2020 and may repeat.

Referring now to FIG. 24, there is shown an embodiment of a localizationsystem according to the invention suitable for use in a configurablemonitoring system. Embodiments of the invention include a method forreceiving modulated backscatter signals using a reader node from one ormore marker tags or marker nodes, receiving a modulated backscattersignal using the reader from an asset tag, estimating parameters of themodulated backscatter signals received from the one or more marker tagsand estimating a parameter of the modulated backscatter signal receivedfrom the asset tag. Any of the tags or nodes in the localization systemcan be configurable monitoring devices. The method further includesdetermining a location estimate for the asset tag, the location estimatebased on the estimated parameters of the modulated backscatter signalsreceived from the one or more marker tags and the estimated parameter ofthe modulated backscatter signal received from the asset tag.

According to another embodiment, a method includes estimating firstparameters of modulated backscatter signals received from a plurality ofmarker tags when a reader is at a first position, estimating a secondparameter of a modulated backscatter signal received from an asset tagwhen the reader is at the first position, moving the reader to a secondposition, estimating third parameters of the modulated backscattersignals received from the plurality of marker tags when the reader is atthe second position, and estimating a fourth parameter of the modulatedbackscatter signal received from the asset tag when the reader is at thesecond position. The method further includes estimating a location ofthe asset tag based on the first parameters, the second parameter, thethird parameters and the fourth parameter.

Embodiments of the invention include means for receiving modulatedbackscatter signals from one or more marker tags, means for receiving amodulated backscatter signal from an asset tag, means for estimatingparameters of the modulated backscatter signals received from the one ormore marker tags, means for estimating a parameter of the modulatedbackscatter signal received from the asset tag and means for determininga location estimate for the asset tag, the location estimate based onthe estimated parameters of the modulated backscatter signals receivedfrom the one or more marker tags and the estimated parameter of themodulated backscatter signal received from the asset tag.

The present invention includes methods and systems for localizing anasset using the modulated backscatter from an asset tag and one or moremarker tags. The modulated backscattered signals from marker tags may beused by a reader and a location module to estimate location of thereader and the asset tags. An asset is any item whose location is ofinterest, and an asset tag is a tag associated with the asset, forexample, by affixing the asset tag to the asset. Assets may be inanimateobjects such as books, or persons, animals, and/or plants.

The methods and systems enable location-enabled inventory, where theestimated locations of tagged assets are determined in an area ofinterest. Furthermore, in embodiments including a mobile reader, themethods and systems can localize asset tags and determine tag motionthroughout a large area and can, for example, take an inventory oftagged assets throughout the large area.

The system includes the reader and the location module and one or moremarker tags that are used to provide location estimates for the assettag based partially on a prior knowledge of the location of each of theone or more marker tags. The location for each marker tag may be storedin a database. A location estimate for an asset tag may be determinedbased on the marker tags. Once the location of an asset tag isestimated, the asset tag may act as a marker tag, and is describedherein as a simulated marker tag.

A location module determines a location estimate for the asset tag usingthe estimated parameters of the modulated backscatter signals receivedfrom one or more marker tags and from the asset tag. The parameters maybe represented by scalar or vector values, and may include, for example,the angle of arrival of the modulated backscatter signals with respectto an axis of the reader, and/or a range (i.e., distance) from themarker tag and/or the asset tag to the reader. Using the known locationsof the marker tags and the estimated parameters, the location estimateof the asset tag can be determined. A location estimate may be arelative location, an absolute location, and/or a zone including themarker tags.

In one example, a zone including an asset tag may be determined bymarker tags at each end of a bookshelf. When the asset tag is affixed toan item on the bookshelf, such as a book, the book may thereby bedetermined to be in the zone, and likewise on the bookshelf. In thisconfiguration, a relative location of the reader may also be determinedby processing the received modulated backscatter signals from the assettag and the marker tags.

With reference to FIG. 24, there is shown a configurable monitoringsystem for localizing using marker tags and asset tags. The localizingsystem of the invention includes methods and systems for localizing anasset using the modulated backscatter from an asset tag and one or moremarker tags. The modulated backscattered signals from marker tags may beused by a reader and a location module to estimate location of thereader and the asset tags. An asset is any item whose location is ofinterest, and an asset tag is a tag associated with the asset, forexample, by affixing the asset tag to the asset. Assets may be inanimateobjects such as books, or persons, animals, and/or plants.

The methods and systems enable location-enabled inventory, where theestimated locations of tagged assets are determined in an area ofinterest. Furthermore, in embodiments including a mobile reader, themethods and systems can localize asset tags throughout a large area andcan, for example, take an inventory of tagged assets throughout thelarge area.

The system includes the reader and the location module and one or moremarker tags that are used to provide location estimates for the assettag based partially on a prior knowledge of the location of each of theone or more marker tags. The location for each marker tag may be storedin a database. A location estimate for an asset tag may be determinedbased on the marker tags. Once the location of an asset tag isestimated, the asset tag may act as a marker tag, and is describedherein as a simulated marker tag.

A location module determines a location estimate for the asset tag usingthe estimated parameters of the modulated backscatter signals receivedfrom one or more marker tags and from the asset tag. The parameters maybe represented by scalar or vector values, and may include, for example,the angle of arrival of the modulated backscatter signals with respectto an axis of the reader, and/or a range (i.e., distance) from themarker tag and/or the asset tag to the reader. Using the known locationsof the marker tags and the estimated parameters, the location estimateof the asset tag can be determined. A location estimate may be arelative location, an absolute location, and/or a zone including themarker tags.

In one example, a zone including an asset tag may be determined bymarker tags at each end of a bookshelf. When the asset tag is affixed toan item on the bookshelf, such as a book, the book may thereby bedetermined to be in the zone, and likewise on the bookshelf. In thisconfiguration, a relative location of the reader may also be determinedby processing the received modulated backscatter signals from the assettag and the marker tags.

FIG. 24 illustrates a configurable monitoring system localizing systemusing marker tags and asset tags. The localizing system comprises areader 2110 and a location module 2170. The reader 2110 may generate atransmitted electromagnetic signal represented by beam 2150. Field ofview (FOV) 2160 may represent the field of view for reception of themodulated backscatter signals received from marker tags 2120 (or markernodes 2120) and/or asset tags 2140 (or asset nodes 2140). FOV 2160 isshown in two-dimensions in FIG. 24 for simplicity, and may be athree-dimensional field of view. A zone 2130 may be a region betweenmarker tag 2120A and marker tag 2120B, as shown for simplicity in twodimensions in FIG. 24. As illustrated in FIG. 24, asset tag 2140B fallswithin zone 2130. In various embodiments, the zone 2130 may also be athree dimensional region (not shown). Thus, one or more marker tags 2120may be used to define zones having two-dimensional and/orthree-dimensional geometries.

In various embodiments, the reader 2110 includes one or more antennas(not shown) for transmitting electromagnetic signals to the marker tags2120 and the asset tag 2140, and one or more antennas for receiving themodulated backscatter signals from the marker tags 2120 and the assettag 2140. The reader 2110 may operate in one or more of the followingmodes: (i) single antenna transmission, multi-antenna reception; (ii)multi-antenna transmission, multi-antenna reception; and/or (iii)multi-antenna transmission, single antenna reception.

The marker tags 2120 and asset tags 2140 communicate with the reader2110 using modulated backscatter signals. Reader 2110 receives modulatedbackscatter signals from the marker tags 2120 and the asset tag 2140,and estimates parameters of the modulated backscatter signals. As usedherein, an estimated parameter of a modulated backscatter signalreceived from a marker tag 2120 and/or an asset tag 2140 includes anymeasurable quantity, characteristic, or information determined and/orestimated from the modulated backscatter signal.

An estimated parameter may include, but is not limited to, an RFIDpreamble, an RFID payload data and/or additional information, a signalstrength of the modulated backscatter signal received from a marker tag2120 and/or an asset tag 2140, an angle of arrival of the modulatedbackscatter signal received from a marker tag 2120 and/or an asset tag2140, an antenna array response for a modulated backscatter signalreceived from a marker tag 2120 and/or an asset tag 2140, a range from amarker tag 2120 and/or an asset tag 2140 to the reader 2110, a time offlight of the modulated backscatter signal from the marker tag 2120and/or asset tag 2140 to the reader 2110. When reader 2110 estimates theparameters of the modulated backscatter signals over time, the locationmodule 2170 may determine a direction of motion of an asset tag 2140and/or a velocity of an asset tag 2140.

The location of the marker tag 2120 may be stored in a database (notshown) that is accessible to the location module 2170. The location ofthe marker tag 2120 may include an absolute or relative location intwo-dimensional (x,y) coordinate space, or an absolute or relativelocation in three-dimensional (x,y,z) coordinate space.

The location module 2170 may provide a location estimate 2180 of theasset tag 2140 by having reader 2110 read (e.g., receive modulatedbackscatter signals) from one or more of the marker tags 2120 and theasset tag 2140 in the FOV 2160 of reader 2110. The location estimate2180 may be an absolute or a relative location estimate of the asset tag2140, may provide a determination that asset tag 2140 is included in thezone 2130, may provide a probabilistic estimate of the absolute orrelative location of asset tag 2140, and/or may provide a probabilisticestimate whether the asset tag 2140 is included in the zone 2130. Forexample, when the reader 2110 reads asset tag 2140B, the location module2170 may compare the location of asset tag 2140B to the location of themarker tags 2120A and 2120B and provide the location estimate 2180including the determination that the zone 2130 includes the asset tag2140B.

In various embodiments, the location module 2170 may provide thelocation estimate 2180 at multiple time instances and/or over multipletime periods. Thus, the location estimate 2180 may be used to determinea direction of motion and velocity of the asset tag 2140. This enables,for example, a reader 2110 located at a doorway to determine whether anasset tag 2140 may be entering or exiting a particular region ofinterest.

In various embodiments, marker tags 2120 and/or asset tags 2140 may bepassive, semi-passive, active, or combinations of these kinds of tags.For example, some marker tags 2120 may be semi-passive in order toprovide a high spatial-resolution identification of zones, while assettags 2140 may be passive tags in order to reduce cost. If a rangebetween reader 2110 and the marker tags 2120 and asset tags 2140 islarger than suitable for passive tags, then both marker tags 2120 andasset tags 2140 may be semi-passive.

Once the location of an asset tag 2140 has been estimated, the asset tag2140 can play the role of a marker tag 2120, thus reducing the densityof marker tags 2120. An asset tag 2140 used in this manner may bereferred to as a simulated marker tag. A zone may thus be determinedbased on one or more simulated marker tags.

FIG. 25 illustrates a localizing system in a shelf application. Themarker tag 2120A may be positioned at one shelf end of shelf 2210, andthe marker tag 2120B at the other end of shelf 2210. A zone 2220 maythen be defined as the region on the shelf between the two marker tags2120A and 2120B. In this application, the location module 2170 mayprovide the location estimate 2180 that includes whether the asset tag2140 is in the zone 2220.

FIG. 26 illustrates a localizing system in a dock door application. Inthis application, a zone including dock door 2310 may be defined by aradius from a marker tag 2120A, and another zone including dock door2320 may be defined by a radius from a marker tag 2120B. Although FIG.26 illustrates a dock door application including two dock doors (dockdoor 2310 and dock door 2320), the localizing system may be used with asingle dock door (not shown), or more than two dock doors (not shown).

The reader 2110 may receive modulated backscatter signals from an assettag 2140 that is passing through dock door 2310. Determining that theasset tag 2140 is passing through dock door 2310 may be based on alocation estimate 2180 that is within a radius from marker tag 2120A.

FIG. 27 is a block diagram of an exemplary transmitter beamformingsystem for use in a configurable monitoring system. The transmitterbeamforming system comprises phase locked loops (PLL) 2410, phaseshifters 2420, modulators 2430, antennas 2440, clock 2450, transmitbeamforming module 2460, transmit data 2470 and marker tag feedback2480. Each of the antennas 2440 may be an individual antenna, or anantenna element. Transmitter beamforming uses two or more antennas 2440to direct the transmitted beam to a certain region in space. In variousembodiments, reader 2110 (FIG. 24) includes transmitter beamformingcapability which enables reader 2110 to select where to direct theenergy of its beam 2150.

In terms of the standard complex baseband representation for passbandsignals, if the transmitter beamforming system has N antenna elements,then the transmitted signal u_(i)(t) from the ith antenna, i=1, . . . ,N , is given by w_(i)s(t), where w_(i) is a complex gain termed the ithbeamforming coefficient, and s(t) is the signal (in general,complex-valued) to be transmitted. In a vector format,

u(t)=(t), . . . , u _(N)(t))^(T),

w=(w _(i) , . . . , w _(N))^(T), and

u(t)=ws(t).

If the signal s(t) is narrowband (i.e., its bandwidth is small relativeto the coherence bandwidth of the channel), then the channel gain fromthe ith transmit element to the marker tag 2120 and/or asset tag 2140 insuch a system can be modeled as a complex scalar h_(i). Defining thechannel vector

h= , . . . , (h _(i) , . . . , h _(N))^(T ,)

the received signal at the marker tag 2120 and/or asset tag 2140 can bemodeled as:

y(t)=h ^(T) ws(t)+n(t),

where n(t) denotes noise.

The modulated backscattered signal from the marker tag 2120 and/or assettag 2140 therefore has power proportional to (h^(T)w)². The channelvector h depends on the location of the marker tag 2120 and/or asset tag2140 relative to the antennas 2440. For example, when antennas 2440 arelinear array with elements spaced by d, the channel vector for a markertag 2120 and/or asset tag 2140 lying at an angle θ relative to thebroadside is given by:

a(θ)=(1, α,α², . . . , α^(N-1))^(T),

where α=exp(^(j2πd sin θ)/λ), and λ denotes the carrier wavelength.Thus, the strength of the modulated backscatter signal from the markertag 2120 and/or asset tag 2140 is related to the location of the markertag 2120 and/or asset tag 2140 relative to the reader 2110.

Using transmitter beamforming, the location module 2170 may provide thelocation estimate 2180 from the modulated backscatter signals asfollows. A main lobe of the transmit beam, such as beam 2150, may bescanned through a region. The beam 2150 is electronically steered usingan array of antennas 2440 by controlling the relative phases andamplitudes of the radio frequency (RF) signals transmitted from theantennas 2440. The strength of the received modulated backscatter signalfrom the marker tags 2120 as a function of the scan angle may beprovided to marker tag feedback 2480 and to the localization module2170. Using this information the location estimate 2180 including theangle of arrival of the modulated backscatter signals received from themarker tags 2120 can be estimated.

The peak in the modulated backscatter signal strength as a function ofthe scan angle, for example, can be used to estimate parameters of thereceived modulated backscatter signal including the angle of arrival.For a high spatial-resolution estimate, suppose that w_(k) is the vectorof transmit beamforming coefficients corresponding to the kth scan,where k=1, . . . , K, and that h(x) is the channel vector from thereader 2110 to a marker tag 2120 and/or an asset tag 2140 at location xrelative to the reader 2110. Here x may denote a three-dimensionalposition, a two-dimensional position, or an angle of arrival and/ordeparture relative to the transmit beamforming array of reader 2110. Thevector of received powers over the K scans is then proportional to:

Q(x)=((h(x)^(T) w ₁)², . . . , (h(x)^(T) w _(K))²).

A comparison of the actual vector of received powers P=(P₁, . . . ,P_(K)) with Q(x) can therefore be used to estimate x from among a set offeasible values for x. For example, consider an array with arrayresponse a(θ). In order to form a beam towards angle θ_(k) on the kthscan, the beamforming coefficients are set to w_(k)=a*(θ_(k)), so thatthe peak of (h^(T)w_(k))² occurs at h=a(θ_(k)). The vector of expectedreceive powers from the marker tag 2120 and/or the asset tag 2140 atangle θ is therefore given by:

Q(θ)=((a(θ)^(H) a(θ₁)², . . . , (a(θ)^(H) a(θ_(K)))²).

A comparison of the actual vector of received powers P=(P₁, . . . ,P_(K)) with Q(θ) can now be used to estimate θ.

This technique generalizes to two-dimensional arrays, which enables theestimation of two angles. While angle estimation may be based oncomparing the shape of P with Q(θ), the strength of P (the receivedsignal strength) can be used to estimate the range of the marker tag2120 and/or the asset tag 2140 relative to the reader 2110. Thus, atwo-dimensional transmit beamforming array can be used in a configurablemonitoring system to estimate the three-dimensional location of a markertag 2120 and/or an asset tag 2140 relative to the reader 2110, bycombining estimates of two angles and a range.

If the marker tag 2120 transmits a modulated backscatter signalincluding a known data sequence, then a correlation against the sequencecan be used to provide an estimate of the parameters of the receivedmodulated backscatter signal. The modulated backscatter signal from amarker tag 2120 and/or an asset tag 2140 is also known as an uplink. Thecorrelation can provide an estimate of the complex baseband channelgain, which is proportional to h^(T)w, and can be used for adaptation ofthe transmit beamforming coefficients w. For example, let sample y[l]correspond to the lth symbol, b[l], transmitted on the uplink. Then:

y[l]=b[l]βh ^(T) w+N[l],

where N[l] denotes noise, and β is the overall complex gain seen on theuplink due to modulated backscatter from the marker tag 2120 and/or theasset tag 2140 and the propagation to reader 2110. Then, the correlation

$\sum\limits_{l}{{y\lbrack l\rbrack}b*\lbrack l\rbrack}$

provides an estimate of βh^(T)w which can be used to adapt w to maximizethe gain (h^(T)w)².

This technique is an implicit feedback mechanism, since the reader 2110is extracting information about, and possibly adapting, the downlinkbased on information extracted from the uplink signal. Alternatively, ifthe data demodulation on the uplink is reliable enough, then this can beused for decision-directed parameter estimation by reader 2110 to reducethe requirement for marker tag 2120 to send a known segment of data.Thus, the symbols b[l]can be replaced by their estimates in such adecision-directed adaptation. The reader 2110 could also estimate theaverage received power on the uplink by, for example, computing anaverage of |y[l]|². The parameter being estimated may include explicitfeedback sent by the marker tag 2120 to the reader 2110. An example ofexplicit feedback is when the marker tag 2120 encodes specificinformation regarding its received signal in the data that it is sendingback in the modulated backscatter signal.

The reader 2110 may also use transmitter beamforming to reduceinterference between conventional RFID systems and/or other transmitterbeamforming systems that may be in the same area. Using the marker tags2120, the reader 2110 may use transmitter beamforming to direct thetransmitted RF energy, such as beam 2150, to desired areas and away fromundesired areas using marker tag feedback 2480 to control transmitbeamforming module 2460. The feedback from the marker tag 2120 can beimplicit or explicit, as discussed herein. Thus, transmitter beamformingand/or power control as described herein can reduce interference andthus accommodate multiple RFID systems and/or multiple readers 2110 inclose proximity.

FIG. 28 is a block diagram of an exemplary receiver beamforming systemwhich can include two or more configurable monitoring devices. Thereceiver beamforming system comprises phase locked loops (PLL) 2510,baseband phase shifters 2520, demodulators 2530, antennas 2540, clock2550, receive beamforming module 2560 and receive data 2570. Each of theantennas 2540 may be an individual antenna, or an antenna element.Receiver beamforming may use two or more antennas 2540 to tune thesensitivity of the reader 2110 to a region in space, such as FOV 2160.In various embodiments, the antennas 2540 may be the same as theantennas 2440 described with reference to FIG. 27. In variousembodiments, reader 2110 includes receive beamforming capability whichenables reader 2110 to determine localization information including anangle of arrival of the modulated backscatter signals received from themarker tags 2120 and the asset tag 2140.

Reader 2110 may include receive beamforming implemented in baseband, asshown in FIG. 28. Using receiver beamforming, the localizing of assettags 2140 can be based on the relationship between the modulatedbackscatter signals received at the antennas 2540 from the one or moremarker tags 2120 and the asset tag 2140. The receive beamforming module360 can estimate the receive array response corresponding to themodulated backscatter signal from a marker tag 2120 and/or an asset tag2140 by correlating the received signals at the antennas 2540 againstknown or estimated data signals.

For example, consider narrowband signaling (in which the signalbandwidth is smaller than the channel coherence bandwidth) and a reader2110 with M antennas. Using the complex baseband representation for thepassband received signals at the M antennas, the received signal for thejth antenna, where j=1, . . . , M, can be written asy_(j)(t)=h_(j)v(t)+n_(j)(t), where v(t) is the signal backscattered bythe tag, h_(j) is the complex channel gain from the tag to the jthantenna element, and n_(j)(t) is the noise seen by the jth antennaelement. Using the vector notation:

y(t)=(y ₁(t), . . . , y _(M)(t))^(T),

h=(h ₁ , . . . , h _(M))^(T),

n(t)=(n ₁(t), . . . , n _(M)(t))^(T), then

y(t)=hv(t)+n(t).

The vector h may be called the receive array response, or the spatialchannel from the marker tag 2120 and/or asset tag 2140 to the reader2110.

It is also useful to consider a discrete-time mode of the precedingrepresentation (possibly obtained by filtering and sampling thecontinuous-time vector signal y(t)), as follows:

y[l]=hb[l]+n[l],

where b[l] may denote the lth symbol transmitted on the uplink. Areceiver beamforming system may form a spatial correlation of the vectorreceived signal with complex-valued receive beamforming coefficients.Thus, let w=(w₁, . . . , w_(M))^(T) denote a vector of complex-valuedbeamforming coefficients, or beamforming weights. Then a receiverbeamforming system may form the inner product:

r(t)=w ^(H) y(t)=(w ^(H) h)v(t)+w ^(H) n(t).

For the discrete-time model, the corresponding inner product may followthe model:

r[l]=w ^(H) y[l]=(w ^(H) h)b[l]+w ^(H) n[l].

An implementation of such a beamforming operation can correspond tophase shifts, implemented in baseband as shown in FIG. 28, as well asamplitude scaling (not shown).

In various embodiments, receive beamforming may be implemented in the RFband using a phase adjustment of the modulated backscatter signalsreceived by individual elements of antennas 2540, according tobeamforming techniques known in the art. The beamforming coefficients wmay be adapted by the receive beamforming module in order to track adesired signal of interest, which might, for example, be known symbolssent on the uplink by the tag. The values of the adapted weights provideinformation regarding the receive array response h. Alternatively, thereceive beamforming module may estimate the receive array response hdirectly from y(t), for example, by correlating it against a set ofknown or estimated symbols. Another quantity of interest is the spatialcovariance matrix C:

C=E[y(t)y ^(H)(t)],

which can be estimated, for example, by summing or averaging the outerproducts y[l]y^(H)[l].

The receive array response corresponding to the marker tag 2120 and/orasset tag 2140 can then be used by the location module 2170 to providethe location estimate 2180 for asset tag 2140, according to techniquesknown in the art. The location module 2170 may also use second orderstatistics, such as the spatial covariance matrix C. In typical RFIDprotocols, the data modulated by a conventional RFID tag includes aknown preamble, followed by a payload that may include a tag identityand/or additional information. In various embodiments, the marker tag2120 and/or the asset tag 2140 may use a known preamble to estimate thereceive array response. In addition to the preamble provided by the RFIDprotocol, a larger training sequence that improves the estimation of thereceive array response can be provided by explicitly configuring thepayload to contain additional information including a known datasegment. For example, for the discrete-time model:

y[l]=hb[l]+n[l],

the receive array response h may be estimated using the correlation

${\sum\limits_{l}{b*\lbrack l\rbrack {y\lbrack l\rbrack}}},$

where the sequence of symbols b[l] is known a priori due to being partof a known preamble or training sequence, as discussed herein.

The receive beamforming module 2560 may combine the signals receivedfrom antennas 2540 using a combination of training and decision-directedadaptation according to techniques known in the art. For example, thereceive beamforming module 2560 may include adaptive algorithms known inthe art based on the linear minimum mean squared error (MMSE) criterion.For example, for the discrete-time model:

r[l]=w ^(H) y[l]=(w ^(H) h)b[l]+w ^(H) n[l],

the receive beamforming coefficients w may be adapted to minimize themean squared error E{|w^(H)y[l]−b[l]|²]. This can be implemented byalgorithms that are known in the art, including least mean squares(LMS), recursive least squares (RLS) or block least squares (BLS),and/or variations thereof. If a marker tag 2120 and/or asset tag 2140 iscommunicating with the reader, and the noise is white, then the MMSEbeamforming coefficients are a scalar multiple of h. Thus, adaptation ofw provides information about the receive array response h. Thebeamforming coefficients w thus determined may be provided to thelocation module 2170. The location module can also be provided with anyadditional information such as the spatial covariance matrix C.

In various embodiments, reader 2110 may perform data demodulationwithout using a receiver beamforming system such as illustrated in FIG.28. In these embodiments, demodulation can be accomplished separatelyfor each antenna (not shown) in an antenna array. Data demodulation canbe performed first using one or more antennas, and then the decisionscan be correlated against the received signals at the different antennaelements to estimate the receive array response. For example, for thediscrete-time model:

y[l]=hb[l]+n[l],

a decision-directed estimation of h may estimate the receive arrayresponse h using the correlation

${\sum\limits_{l}{b*\lbrack l\rbrack {y\lbrack l\rbrack}}},$

where the estimates of the symbols b[l] are obtained from demodulators.

As described herein, the receiver array response h may be estimated byvarious methods including direct estimation by correlation of the vectorreceived modulated backscatter signal against known or estimatedsignals, and indirect estimation by adapting receive beamforming weightsw. Estimates of the receive array response may be used by the locationmodule 2170 to provide the location estimate 2180 for the marker tag2120 and/or asset tag 2140, relative to the reader 2110, since thereceive array response h depends on the location of the marker tag 2120and/or asset tag 2140 relative to the antennas 2540 in the receiveantenna array.

For example, when antennas 2540 are a linear array with elements spacedby d, the channel vector for a marker tag 2120 and/or asset tag 2140 atan angle θ relative to the broadside is given by:

a(θ)=(1, α,α², . . . , α^(N-1))^(T),

where α=exp(^(j2πd sin θ)/λ) and λ denotes the carrier wavelength. For aline of sight

(LOS) link between the antennas 2540 and the marker tag 2120 and/orasset tag 2140, the direction in which the marker tag 2120 and/or assettag 2140 lies, relative to the current position of the antennas 2540,can be estimated by maximizing |a^(H)(θ)h| as a function of θ over itspermissible range. For an embodiment where antennas 2540 are atwo-dimensional antenna array, two angles may be estimated. Furthermore,the received signal strength can be used to estimate the range, whichthen enables three-dimensional location. Other techniques known in theart for estimating the range can also be used, such as using frequencymodulated continuous wave (FMCW) waveforms.

Once the location of the marker tags 2120 and/or asset tag 2140 relativeto the reader 2110 have been determined by the location module 2170, acomparison of these locations can be used to determine the locationestimate 2180 of the asset tag 2140 relative to the marker tags 2120.Thus, if the absolute location of the marker tags 2120 is known, thenthe absolute location of the asset tag 2140 can be determined.Alternatively, the location module 2170 may compare location-relatedparameters such as transmit or receive beamforming coefficients, orestimates of the receive array response, in order to provide thelocation estimate 2180 for the asset tag 2140 relative to the markertags 2120. Such a location estimate 2180 may be quantized to a zone, asdescribed herein, instead of being an explicit estimate in atwo-dimensional or three-dimensional coordinate system. As discussedwith reference to FIG. 24, FIG. 25 and FIG. 26, a zone may be defined asa region around one or more marker tags 2120, without requiring that theabsolute coordinates of the marker tags are known.

If the antennas 2440 described with reference to FIG. 27 and theantennas 2540 described with reference to FIG. 28 are the same antennaarray, the beamforming coefficients determined by receive beamformingmodule 2560 may be used for transmission by transmit beamforming module2460, thereby directing beam 2150 more precisely to the region of amarker tag 2120 and/or an asset tag 2140. Alternatively, to reduceinterference from marker tags 2120 in a particular region, the transmitbeamforming module 2460 may synthesize a null in the direction ofparticular marker tags 2120 by adapting the transmit beamformingcoefficients to be near-orthogonal to the receive beamformingcoefficients.

A reader 2110 including transmitter and/or receiver beamforming mayprovide improved performance by using space division multiple access(SDMA) methods known in the art. For example, reader 2110 can direct itstransmitted energy in beam 2150 to a small region, thereby reducing thenumber of marker tags 2120 that are illuminated by beam 2150. In variousembodiments, the use of SDMA may simplify the task of singulation. For areader 2110 including receive beamforming, multiuser detectiontechniques and algorithms such as MUSIC can be used to successfullydecode simultaneous responses from multiple marker tags 2120 based onthe differences in their receive array responses. Furthermore, if themarker tag 2120 payload includes data encoded in a direct sequencespread spectrum format, then multiple tags may be read at the same timeby employing code division multiple access (CDMA) techniques known inthe art to successfully decode multiple responses by received by reader2110. In a reader 2110 with receiver beamforming capabilities, such CDMAtechniques can be used in conjunction with SDMA.

Reader 2110 may also be used to determine range estimates. The geometryfor a reader 2110 is analogous to radar and/or sonar since the modulatedbackscatter signals from marker tags 2120 and asset tags 2140 areelectronically reflected back to reader 2110. Therefore, according tomethods known in the art, radar and/or sonar techniques can be used toestimate range information. For example, the reader 2110 can transmitbeam 2150 including a frequency modulated continuous wave (FMCW)waveform instead of a continuous wave (CW) tone. It can process thereturn from the marker tag 2120 and/or asset tag 2140 to detect thefrequency difference between the transmitted FMCW waveform and thereceived FMCW waveform, and thereby estimate the range as may be done inFMCW radar. Reader 2110 may be used to determine range information usingthe strength of a modulated backscatter signal received from a markertag 2120 and/or an asset tag 2140.

FIG. 29 illustrates a localizing system in a multipath environment.Reader 2110 and location module 2170 may localize marker tags 2120and/or asset tags 2140 in the presence of multipath components fromreflecting or scattering objects. One such reflecting or scatteringobject is a ground surface. As illustrated in FIG. 29, a multipathenvironment may include reader 2110 at a location (x, y, z), ground2630, a marker tag 2120 at location (x_(t), y_(t), z_(t)). The reader2110 receives direct backscatter 2610 from marker tag 2120, and groundreflection 2620.

In a simple line of sight (LOS) environment without a ground reflection2620, a maximum likelihood (ML) estimate of the location of the markertag 2120 and/or the asset tag 2140 corresponds to maximizing thecorrelation of the received array response against the array manifold.However, for a multipath environment, the ML estimate depends on thegeometry. In one example, a dominant multipath component may be theground reflection 2620 reflected from ground 2630. Other reflecting orscattering objects between the reader 2110 and marker tag 2120 and/orasset tag 2140 may also produce multipath components.

The complex baseband received array response corresponding to themultipath environment illustrated in FIG. 29 may be modeled by:

h=α ₁ a ₁(x _(t) , y _(t) , z _(t))+α₂ a ₂(x _(t) , y _(t) , z _(t))+N

where a₁is the array response corresponding to the direct backscatter2610 (LOS path), a₂ is the array response corresponding to path from theground reflection 2620, α₁, α₂ are complex gains corresponding to thesepaths and depend on the propagation environment, and may be unknown, andN is noise. The receive array response h above may denote an estimate ofthe receive array response, obtained using one of the techniquesdiscussed herein, and the noise N may be interpreted as estimationnoise, which is typically well approximated as white and Gaussian.

One approach to modeling these complex gains is to obtain a joint MLestimate of the complex gains and the location of marker tag 2120,(x_(t), y_(t), z_(t)), by performing the minimization:

min_(α) ₁ _(α) ₂ min_((x,y) _(t) _(,z) _(t) ₎(y−α ₁ a ₁(x _(t) , y _(t), z _(t))+α₂ a ₂(x _(t) , y _(t) , z _(t)))^(H)(y−α ₁ a ₁(x _(t) , y_(t) , z _(t))+α₂ a ₂(x _(t) , y _(t) , z _(t)))

where H is the conjugate transpose and the minimization is optimal whenthe noise, N, is additive white Gaussian.

One solution known in the art is to choose a location of marker tag 2120(x_(t), y_(t), z_(t)) that minimizes the projection of y orthogonal tothe subspace spanned by a₁(x_(t), y_(t), z_(t)) and a₂(x_(t), y_(t),z_(t)). The search for the best estimate of the location (x_(t), y_(t),z_(t)) can be constrained further based on additional information (e.g.,range estimates, or prior knowledge of the distance of the reader 2110from the location estimate of the marker tag 2120.)

Other solutions known in the art include use of algorithms such as MUSICor ESPRIT for finding the dominant multipath components, based on thespatial correlation matrix. In general, finding the best fit locationfor marker tag 2120 for a particular receive array response can beachieved using standard ML or Bayesian techniques that take into accountmodels of the multipath environment.

For a rich scattering environment, where the multipath is not sparseenough to model as described herein, the dependence of the receive arrayresponse for the location of marker tag 2120 may not be correctlymodeled as described herein. However, the received array response stillvaries smoothly with the location of marker tag 2120. Thus, if one ormore marker tags 2120 are placed densely enough, then a comparison ofthe array response for an asset tag 2140 (FIG. 24) with those of markertags 2120 (e.g., by computing the normalized correlation between theestimated parameters) can be used to estimate the location of the assettag 2140. If h_(a) and h_(b) are the estimated receive array responsesfor tags a and b, then the normalized correlation may be defined as:

$\frac{{h_{a}^{H}h_{b}}}{\sqrt{\left( {h_{a}^{H}h_{a}} \right)\left( {h_{b}^{H}h_{b}} \right)}}.$

For example, if the received array response is highly correlated withthose for the marker tags 2120 on a shelf 2210 (FIG. 25), as determinedby a clustering algorithm, then one would estimate that the asset tag2140 is on the shelf 2210.

FIG. 30 illustrates a localizing system in a two-dimensional mobilereader configuration. In various embodiments, the reader 2701 may bemobile, i.e., the reader 2701 may be moved from a first position to asecond position (indicated as reader 2702). A mobile readerconfiguration may used to take an inventory of asset tags 2140 over anentire store.

In the mobile configuration, reader 2110 may receive modulatedbackscatter signals from a plurality of marker tags 2120 and an assettag 2140 using a reader 2701, where reader 2701 is an embodiment ofreader 2110 at the first position. Then, the reader 2702 may receivemodulated backscatter signals from the plurality of marker tags 2120 andthe asset tag 2140, where reader 2702 is an embodiment of reader 2110 atthe second position.

As illustrated in FIG. 30, an angle 2710 may be defined as an anglebetween the marker tag 2120A and an axis of reader 2701. Likewise, anangle 2720 may be defined between the asset tag 2140 and the axis ofreader 2701, and an angle 2730 may be defined as an angle between themarker tag 2120B and the axis of reader 2701. Range 2715 is defined asthe distance between the marker tag 2120A and the reader 2701. Likewise,range 2725 is defined as the distance between the asset tag 2140 and thereader 2701, and range 2735 is defined as the distance between themarker tag 2120B and the reader 2701.

Similarly, angles 2740 and 2760 may be defined from the marker tags2120A and 2120B, respectively, and the axis of reader 2702. Angle 2750may be defined from the asset tag 2140 and the axis of reader 2702.Likewise, ranges 2745 and 2765 may be defined from the marker tags 2120Aand 2120B, respectively, and the reader 2702. Range 2755 may be definedas the distance from asset tag 2140 and reader 2702.

In one embodiment, estimated parameters of the modulated backscattersignals received from marker tags 2120A and 2120B include the angles2710 and 2730 (with respect to the axis of reader 2701), and angles 2740and 2760 (with respect to the axis of reader 2702). In this embodiment,the estimated parameters of the modulated backscatter signals receivedfrom the asset tag 2140 include the angles 2720 and 2750.

Since the positions of the marker tags 2120A and 2120B are known, thelocation module 2170 may provide the location estimate 2180 for theasset tag 2140 using the locations of marker tags 2120A and 2120B, theangles 2710, 2720, 2730, 2740, 2750, 2760, and geometry, by firstestimating the locations of the reader 2701 and the reader 2702. Thelocation of the reader 2701 can be estimated using the locations of themarker tags 2120A and 2120B, the angles 2710 and 2730, and simplegeometric calculations. The location of the reader 2702 can likewise beestimated.

The location module 2170 may provide the location estimate 2180 for theasset tag 2140 as follows: denote (x₁, y₁) the location of marker tag2120A, (x₂, y₂) the location of marker tag 2120B, θ₁ the angle 2730, andθ₂ the angle 2710. Then, the location (a₁, b₁) of reader 2701 can beestimated by solving the following equations:

${\frac{y_{1} - b_{1}}{a_{1} - x_{1}} = {\tan \; \theta_{1}}},\mspace{14mu} {\frac{y_{2} - b_{1}}{x_{2} - a_{1}} = {\tan \; {\theta_{2}.}}}$

The location module 2170 may estimate the location of the reader 2702using the locations of the marker tags 2120A and 2120B, the angles 2740and 2760, and similar geometric calculations.

Subsequently, the location of the asset tag 2140 may be estimated usingthe estimates of the locations of the readers 2701 and 2702, the angles2720 and 2750, and similar geometric calculations. Although FIG. 30 isshown in two dimensions for simplicity, the location of the asset tag2140, reader 2701 and reader 2702 may also be estimated in threedimensions using similar geometrical calculations generalized tothree-dimensions.

In various embodiments, estimated parameters of the modulatedbackscatter signals received from marker tags 2120A and 2120B includethe ranges 2715 and 2735 (to reader 2701) and ranges 2745 and 2765 (toreader 2702). In these embodiments, the estimated parameters of themodulated backscatter signals received from the asset tag 2140 includethe ranges 2725 and 2755.

Since the positions of the marker tags 2120A and 2120B are known, thelocation module 2170 may provide the location estimate 2180 for theasset tag 2140 using, for example, the locations of marker tags 2120Aand 2120B, the ranges 2715, 2725, 2735, 2745, 2755, 2765, and geometry.By first estimating the locations of the reader 2701 and the reader2702, the location of the asset tag 2140 may be estimated. The locationof the reader 2701 can be estimated using the locations of the markertags 2120A and 2120B, the ranges 2715 and 2735, and geometriccalculations. The location of the reader 2701 may be likewise estimated.

The location module 2170 may estimate the location of an asset tag 2140as follows: denote by (x₁, y₁) the location of marker tag 2120A, (x₂,y₂) the location of marker tag 2120B, r₁ the range 2715, and r₂ therange 2735. Then, the location (a₁, b₁) of reader 2701 can be estimatedby solving the following equations:

(a ₁ −x ₁)²+(b ₁ −y ₁)² =r ₁ ², (a ₁ −x ₂)²+(b ₁ −y ₂)² =r ₂ ².

There are two possible solutions, corresponding to the two intersectionsof circles of radius r₁ and r₂ centered at the marker tags 2120A and2120B, respectively. (If the circles do not intersect, then there is nosolution to the preceding equation.) The solution that corresponds tothe location of the reader 2701 can be determined based on, for example,by knowing which side of the marker tags 2120A and 2120B the reader 2110is on.

The location module may estimate the location of the reader 2702 usingthe locations of the marker tags 2120A and 2120B, the ranges 2745 and2765, and similar geometric calculations. Subsequently, the locationestimate 2180 of the asset tag 2140 may be estimated using the estimatesof the locations of the readers 2701 and 2702, the ranges 2725 and 2755,and similar geometric calculations. The location of the asset tag 2140,reader 2701 and 2702 may also be estimated in three dimensions usinggeometry.

In various embodiments, the estimated parameters of the modulatedbackscatter signals received from marker tags 2120 and/or asset tag 2140are received array responses. In an environment with multipathpropagation, location module 2170 may provide the location estimate 2180for the marker tags 2120 and/or asset tag 2140 using the received arrayresponses and may use prior knowledge of, or models of, the multipathenvironment. For example, if the multipath environment consistsprimarily of a line-of-sight path and a ground reflection, asillustrated in FIG. 29, then a ML or Bayesian approach may be used forestimating the locations of the reader 2110 (e.g., reader 2701 andreader 2702), marker tags 2120 and asset tag 2140 by taking into accountthe complex gains associated with each path.

With reference to FIG. 31A, there is shown a configurable monitoringdevice system 3000. The configurable monitoring device system 3000 issuitable for beamforming and localization of devices in tagcommunications systems including tag communications systems havingconfigurable monitoring devices, according to an embodiment of thesystem and method of the invention. The configurable monitoring devicesystem 3000 can include configurable monitoring devices 3002, 3004. Theconfigurable monitoring devices 3002, 3004 can be configured to operateas beacons 3002, 3004, each having a plurality of signal ranges.Additionally, the configurable monitoring device system 3000 can includeany number of configurable monitoring devices configured to operate asany other types of nodes. For example, six configurable monitoringdevices can be configured to operate as tags 3012 a-f within theconfigurable monitoring device system 3000. While the configurablemonitoring device system 3000 is shown in two-dimensions, it will beunderstood that it can be extended into three-dimensions.

When the tags 3012 a-f are within the areas reached by the signals fromthe beacons 3002, 2004 they can respond to the beacon signals in aconventional manner, for example by backscatter. The response of thetags 3012 a-f to the beacon signals from the configurable monitoringdevices 3002, 3004 can be reported to an information gathering node. Forexample they can report to the monitoring terminal 62, by way of agateway node 64, as previously described with respect to the monitoringsystem 60 shown in FIG. 1. The response of the tags 3012 a-f to thebeacon signals can be reported to the information gathering node by wayof a mesh of tags 68 a-i, by way of communications routing or taglocating nodes 66, directly to reader modules, as also shown in FIG. 1,or by any other method.

In an illustrative case, each beacon 3002, 3004 can have two signalranges, a weak, short range and a strong, long range. The radius 3006 ofthe weak signal from the beacon 3002, and the radius 3008 of the strongsignal from the beacon 3004 are illustrated in FIG. 31A. As shown, thetags 3012 a,e,f are not in the range of the weak signal from the beacon3002. Thus, the tags 3012 a,e,f do not respond to the signal from thebeacon 3002, and the monitoring terminal 62 of the monitoring system 60can determine that items tagged with the tags 3012 a,e,f are not withinthe radius 3006 of the beacon 3004 from the lack of such response.

Additionally, as illustrated in FIG. 31A, the tags 3012 b,c,d are withinthe radius 3006 of the beacon 3002, and they do respond to the signalfrom the beacon 3002. Therefore, the monitoring terminal 62 within themonitoring system 60 can determine that items having the tags 3012 b,c,dare within the radius 3006 of the beacon 3002, based on the informationit receives from the signals transmitted by the beacon 3002 in theconfigurable monitoring device system 3000.

Accordingly, useful localization information with respect to itemstagged with the tags 3012 a-f can be obtained by the monitoring terminal62 using the signals provided by the beacon 3002. However, based on theinformation whether the tags respond to the signal from the beacon 3002,it is only possible to determine whether the tags 3012 a-f are insidethe radius 3006 or outside the radius 3006. It is not possible todetermine where inside the radius 3006 or where outside the radius 3006they are located.

In the same manner, the monitoring terminal 62 can determine that thetags 3012 a,b,f are not within the radius 3008 of the beacon 3004, andthat the tags 3012 c,d,e are within the radius 3008. However, based onthis information alone, it is only possible to determine whether thetags 3012 a-f are inside the radius 3008 or outside the radius 3008. Itis not possible to determine where inside or outside the radius 3008they are located based on this information.

By performing logical or arithmetic operations on the data from the twobeacons 3002, 3004, additional localization of some of the tags 3012 a-fcan be performed. For example, since the tags 3012 c,d are within bothradius 3006 and radius 3008, a determination can be made that they aresomewhere in the region 3010, where the ranges of the beacons 3002, 3004overlap with each other. Any number of additional beacons can beprovided in order to further localize the configurable monitoringdevices of the invention in this manner. Furthermore, the beacons 3002,3004 are understood to be any configurable monitoring devices or othertag communication device that can transmit radio frequency signals atthe desired power levels and at the desired times.

Determinations can be made which tags 3012 a-f are within each range ofeach beacon as the beacons cycle through their multiple power levels.For example, a tag 3012 a-f can be located within the radius of thestrong signal from a beacon, but not within the radius of the weaksignal from the same beacon. Under these circumstances the tag 3012 a-fcan be localized to a donut shaped region around the beacon in thetwo-dimensional case. Logical or arithmetic operations can be performedon all of the range information obtained using the foregoing techniques.

Additionally, as previously described, the various nodes of a meshsystem formed by the configurable monitoring devices of the inventioncan communicate with each other directly. For example, the tags 3012 a,bare close enough to communicate with each other as shown by the arrow3014. Thus, using tag to tag communication, tag 3012 a can communicateby way of the mesh that it can receive a communication from tag 3012 b,or tag 3012 b can communicate by way of the mesh that it can receive acommunication from tag 3012 a, or both. Alternately, the tags 3012 a,bcan communicate this information in a different manner. Since the tags3012 a,b can communicate with each other, they can thus provide themonitoring terminal 62 with information that they are within range ofeach other.

Logical or arithmetic operations can be performed on informationregarding communications such as the communications between the tags3012 a,b, of a mesh system, along with the information whether the tags3012 a-f are within the various signal ranges of the beacons 3002, 3004.These operations can permit a determination to be made, for example,that the tag 3012 a is outside the radius 3006 of the beacon 3002, butwithin the range of the tag 3012 b, thereby providing some furtherlocalization information for the tags 3012 a,b. The information that thetags 3012 a,b are within range of each other can be reported to theinformation gathering node, such as the monitoring terminal 62, by wayof the mesh of tags 68 a-i, the communications routing or tag locatingnodes 66, directly to reader modules, or by any other method.

With reference to FIGS. 31B-C, there are shown two-dimensional andthree-dimensional representations, respectively, of a configurablemonitoring device system 3050. The configurable monitoring device system3050 is suitable for beamforming and localization of configurablemonitoring devices according to an embodiment of the system and methodof the invention. The configurable monitoring device system 3050 caninclude the elements of the configurable monitoring system 3000, withthe addition of a configurable monitoring device 3052. In a preferredembodiment of the invention the configurable monitoring device 3052 caninclude a collocated reader module and beamformer module having anynumber of beamformer nodes to provide a reader/beamformer 3052.Accordingly, calculations of power, phase and modulated data can beperformed for any number of channels and any number of array elementswithin the beamformer module provided within the reader/beamformer 3052.In another preferred embodiment, the reader and the beamformer modulesmay be provided as separate devices.

Using the beamforming techniques of the invention, the beamformer modulewithin the reader/beamformer 3052 can generate a radio frequencyidentification signal 3054, as previously described with respect to theradio frequency identification signal 1160 shown in FIG. 14. The radiofrequency identification signal 3054 can be used to provide furtherlocalization information for localizing the tags 3012 a-f. The furtherlocalization information obtained using the radio frequencyidentification signal 3054, such as angle of arrival information, timeof flight information, phase information, etc. can be combined with thelocalization information obtained by the configurable monitoring system3000, to further localization the tags 1012 a-f. For example, the radiofrequency identification signal 3054 can be used to narrow the locationof the tag 3012 d from anywhere in the region 3010 to the region 3056.Thus, it will be understood that when a tag such as the tag 3012 d islocalized in this manner, the range information and the angleinformation used to localized it can be represented by backscattersignals from at least two different sources of electromagnetic signals,in this case a beacon 3002, 3004 and the reader/beamformer 3052.

Furthermore, logical or arithmetic operations can be performed on anyinformation or sets of information obtained by the configurablemonitoring device systems 3000, 3050, 3080 (described below) in order tofurther localize the configurable monitoring devices. For example, angleof arrival information or phase angle information can be logically orarithmetically combined with distance information regarding the distancebetween a tag and one or more beacons or readers. The angle of arrivalinformation or phase angle information with respect to marker tagsand/or asset tags can be combined with distance information regardingthe distance between two or more communicating configurable monitoringdevices in a mesh. Power information can be combined with distanceinformation, etc. The distance information can be communicated to aninformation gathering node by way of the mesh or any other paths.

As previously described, the beamformer module within thereader/beamformer 3052 can receive control radio frequency informationfrom the reader module for controlling the beamforming operations.Selected configurable monitoring devices 3012 a-f within theconfigurable monitoring device system 3050 can be configured to operateas calibration modules, or calibration nodes for calibrating thebeamformers of the reader/beamformer 3052. For example, selected devices3012 a-f can be configured to operate as calibration modules 1140, asdescribed above with respect to the interrogation zone 1170. The controlradio frequency information from the reader module can thus be based oncalibration data radio frequency information received from calibrationmodules and tags within the interrogation zone of the reader module.

In various embodiments, the reader module may communicate with thebeamforming module within the reader/beamformer 3052 via beamformingcontrol radio frequency connections, hardwired connections, or both. Aconfigurable monitoring device 3012 a-f, configured as a calibrationmodule within the interrogation zone, can measure the net receivedsignal from the beamforming module via the radio frequencyidentification signal, and communicate with the reader module to reportthe measurements of the received signal.

A control feedback control loop is thus formed comprising one or more ofthe calibration modules, the reader module, and the beamforming modulewithin the reader/beamformer 3052. The control feedback loop is used toadjust the power and phase of the radio frequency identification signalfrom the beamformer module, so as to increase the strength and/orsignal-to-noise ratio of the radio frequency identification signalreceived at the calibration node.

As previously described with respect to the beamforming system 1200, theconfigurable monitoring device system 3050 can include a reader node,and a plurality of beamformer nodes. A plurality of beamforming controlchannel antennas and RFID channel antennas corresponding to theplurality of beamforming nodes are also included. Beamforming controlhardwired connections and beamforming control radio frequencyconnections can also be included for the plurality of beamforming nodes.One or more calibration nodes, one or more RFID tags located in theinterrogation zone, the calibration data radio frequency connection, theradio frequency identification data, and the radio frequencyidentification signal can also be included. The reader node may use anystandard read/write protocols (e.g., governing the timing ofacknowledgements, retransmissions, multiple-access arbitration) of aconventional RFID reader.

The calibration nodes take measurements of the radio frequencyidentification signals, such as net received power or signal-to-noiseratio, and relay feedback regarding this information back to thebeamforming nodes, either directly or through the reader node. Thebeamformer feedback control loop is employed by the beamforming nodes toadapt the phases and/or transmitted power of the radio frequencyidentification signals to maximize the power or signal-to-noise ratioreceived by the calibration node, and hence any RFID tag circuitry inthe interrogation zone.

In various embodiments, the beamforming feedback system may use any of anumber of feedback control loop iterative algorithms. The feedbackcontrol loop algorithms maximize the quality of the net received signalat the calibration node, which may be determined by the net receivedpower or the signal-to-noise ratio. The feedback control loop mayprovide a direct estimate of the average received power at thecalibration node, and/or an estimate of both the power and phaseevolution of the received signal. Alternatively, the feedback controlloop may provide an estimate of the difference in received powerscorresponding to different phase settings employed by the beamformingnodes. The feedback control loop can be employed for adaptation of acentralized antenna array.

Any algorithm that is used in such centralized settings can be employedin a distributed setting as well, as long as the beamforming weightw_(i) for the ith array element depends on its prior values and on thefeedback. In this case, the ith beamforming node becomes equivalent tothe ith array element in a centralized adaptive antenna array. Forexample, the Mudumbai et al. algorithm may be applied as previouslydescribed, wherein the beamforming weight for the ith beamforming node,w_(i)=e^(jφ) is iteratively calculated after random perturbations of itsphase. The received power P reported to the reader node by the controlfeedback loop control under these conditions, can be calculated andoptimized.

With reference to FIG. 31D, there is shown a configurable monitoringdevice system 3080. The configurable monitoring device system 3080 issuitable for beamforming and localization of configurable monitoringdevices configured as marker tags 3082 a,b and asset tags such as theasset tag 3084 according to a preferred embodiment of the system andmethod of the invention.

The reader 3052 of the configurable monitoring device system 3080 maygenerate a electromagnetic signal represented by the beam 3054. Field ofview (FOV) 3088 of the reader 3052 may represent the field of view forreception of the modulated backscatter signals received from the markertags 3082 a,b and/or the asset tag 3084. The FOV 3088 is shown intwo-dimensions in FIG. 31D for simplicity, and may be extended to athree-dimensional field of view. A zone 3086 may be defined between themarker tag 3082 a and the marker tag 3082 b, as shown for simplicity intwo dimensions in FIG. 31D. The asset tag 3084 falls within the zone3086. In various embodiments, the zone 3086 may also be a threedimensional region (not shown). Thus, one or more marker tags 3082 a,bmay be used to define zones having two-dimensional and/orthree-dimensional geometries for localizing asset tags such as the assettag 3084.

In various embodiments, the reader 3052 includes one or more antennas(not shown) for transmitting electromagnetic signals to the marker tags3082 a,b and the asset tag 3084. Additionally, the reader 3052 caninclude one or more antennas or virtual antennas for receiving themodulated backscatter signals from the marker tags 3082 a,b and theasset tag 3084. The reader 3052 may operate in one or more of thefollowing modes: (i) single antenna transmission, multi-antennareception; (ii) multi-antenna transmission, multi-antenna reception;and/or (iii) multi-antenna transmission, single antenna reception.

The marker tags 3082 a,b and the asset tag 3084 can communicate with thereader 3052 using modulated backscatter signals. The reader 3052receives modulated backscatter signals from the marker tags 3082 a,b andthe asset tag 3084, and estimates parameters of the modulatedbackscatter signals. An estimated parameter of a modulated backscattersignal received from a marker tag 3082 a,b or an asset tag 3084 caninclude any measurable quantity, characteristic, or informationdetermined and/or estimated from the modulated backscatter signal aspreviously described. The location of a marker tag 3082 a,b may includean absolute location or a relative location in two-dimensional (x,y)coordinate space, or an absolute or relative location inthree-dimensional (x,y,z) coordinate space.

The location module 3090 may provide a location estimate 3095 of theasset tag 3084 by having the reader 3052 read (e.g., receive modulatedbackscatter signals from) one or more of the marker tags 3082 a,b andthe asset tag 3084 in the FOV 3088 of reader 3052. The location estimate3095 may be an absolute or a relative location estimate of an asset tag3084 a,b. It may provide a determination that the asset tag 3084 isincluded in the zone 3086. It may also provide a probabilistic estimateof the absolute or relative location of asset tag 3084, and/or it mayprovide a probabilistic estimate whether the asset tag 3084 is includedin the zone 3086. For example, when the reader 3052 reads the asset tag3084, the location module 3090 may compare the location of asset tag3084 to the location of the marker tags 3082 a,b, and provide thelocation estimate 3095, including the determination that the zone 3086includes the asset tag 3084. Furthermore, the location informationobtained in this manner may be logically combined with the locationinformation obtained according to the responses of various configurablemonitoring devices to the beacon signals of the beacons 3002, 3004 andcommunications between the nodes of the mesh, as described above.

The marker tag 3082 a may be positioned at one end of a shelf, and themarker tag 3082 b at the other end of the shelf. A zone may be definedas the region on the shelf between the two shelf marker tags 3082 a,b.In this application, the location module 3090 may provide the locationestimate 3095 that includes whether the asset tag 3084 is on the shelf.In another application, a zone including a dock door may be defined by aradius from a marker tag 3082 a,b located at the dock door. The reader3052 may then receive modulated backscatter signals from an asset tag3084 that is passing through the dock door. Determining that the assettag 3084 is passing through the dock door may be based on a locationestimate 3095 that the asset tag 3084 is within a radius from marker tag3082 a,b.

The transmitter beamforming system within the reader/beamformer 3052comprises phase locked loops, phase shifters, modulators, antennas,clock, transmit beamforming modules, transmit data and marker tagfeedback. In another embodiment (not shown) the beamformer and thereader can be provided as separate devices rather than being collocated.Each of the antennas may be an individual antenna, or an antennaelement. Transmitter beamforming uses two or more antennas to direct thetransmitted beam to a certain region in space. In various embodiments ofthe invention, the system can include transmitter beamforming capabilitywhich enables the reader to select where to direct the energy of itsbeam.

For N antenna elements the transmitted signal u_(i)(t) from the ithantenna, i=1, . . . , N , is given by w_(i) s(t),where w_(i) is acomplex gain termed the ith beamforming coefficient, and s(t) is thesignal (in general, complex-valued) to be transmitted. In a vectorformat,

u(t)=(u ₁(t), . . . , u _(N)(t))^(T),

w=(w ₁ , . . . , w _(N))^(T), and

u(t)=ws(t).

If the signal s(t) is narrowband, the channel gain from the ith transmitelement to the tag can be modeled as h_(i). Defining the channel vector

h=(h ₁ , . . . , h _(N))^(T),

the received signal at the tag can be modeled as:

y(t)=h ^(T) ws(t)+n(t),

where n(t) denotes noise.

The modulated backscattered signal from a tag therefore has powerproportional to (h^(T)w)². The channel vector h depends on the locationof the tag relative to the antennas. If the antennas are a linear arrayspaced by d, the channel vector for a tag at an angle θ relative to thebroadside is:

a(θ)=(1,α,a ², . . . , α^(N-1))^(T),

where α=exp(^(j2πd sin θ)/λ), and λ is the carrier wavelength. Thestrength of the signal from the tag is related to the location of thetag relative to the reader.

The location estimate 3095 can be obtained as follows. A main lobe ofthe transmit beam may be scanned through a region. The beam iselectronically steered using an array of antennas to control therelative phases and amplitudes of the signals transmitted from theantennas. The strength of the signal from the marker tags 3082 a,b as afunction of the scan angle may be provided to the marker tag feedbackmodule and to the location module 3090. Using this information,including the angle of arrival of the modulated backscatter signalsreceived from the marker tags 3082 a,b, the location estimate 3095 canbe estimated. Accordingly, the configurable monitoring device system3080, configured to include a reader/beamformer can use information,such as angle and phase information, to determine whether a tag, such asthe asset tag 3084, is located in a zone between marker tags. Thisinformation can be combined with location information obtained accordingto the responses of various configurable monitoring devices to thebeacon signals of the beacons 3002, 3004 as previously described inorder to further localize tags.

With reference to FIG. 32, there is shown a two-dimensionalrepresentation of a configurable monitoring device system 4000 similarto system 3050 as described above. The radio frequency identificationsignal 3054 can be used in combination with a second radio frequencyidentification signal 3055 to provide vector information 4010 forlocalizing the tag 3012 c. The further vector information 4010 may beobtained by comparing the radio frequency identification signals 3054and 3055 attributes, such as angle of arrival information, time offlight information, phase information, etc., to compute a velocityand/or direction of movement of the tag 3012 c between the time T1 thatthe responses to the radio frequency identification signal 3054 isreceived by reader/beamformer 3052 and the time T2 radio frequencysignal 3055 is received by reader/beamformer 3052.

The vector information 4010 can be used in a variety of ways to inferthat possible future locations of tag 3012 c are more or less probable.For example, rules about the motion of tags can be devised a priori orby empirical observations of actual store operations, shopping, andtheft events. Such rules could depend on the context in which the tag3012 c is situated. For instance, it could be inferred that a tag movingslowly along a shopping aisle is being moved by a shopper, and thereforeis likely that to continue to move slowly and eventually be brought to astore point-of-sale such as a cash register location. Similarly, in anopen store floor plan, a tag in motion may be assumed that a tag inmotion is 50% likely to continue in the observed direction of motion,and 25% likely to turn left, and 25% likely to turn right.

Referring to FIG. 32, there are shown three likely locations for tag3012 c at a time T3 after vector information 4010 is obtained. Forpurposes of illustration, the system may be configured to place a 50%likelihood that the tag 3012 c continued moving as observed at T2 and istherefore now in region 4011. It is 25% likely that it turned left andis now in region 4012, and 25% likely that it turned right and is inregion 4013.

If the system next receives the information at T3 that tag 3012 c iswithin range of beacon 3004, it can be inferred that the location of tag3012 c is most likely within region 4012. This inference can be drawnfrom a combination of the prior location information, prior vectorinformation, and rules regarding the probable motion of tags. It is notnecessary to obtain another reading from reader/beamformer 3052 or othersystem components before drawing the inference.

The embodiments discussed herein are illustrative of the presentinvention. As these embodiments are described with reference toillustrations, various modifications or adaptations of the specificelements or methods described may become apparent to those skilled inthe art. All such modifications, adaptations, or variations that rely onthe teachings of the present invention, and through which theseteachings have advanced the art, are considered to be in the spirit andscope of the present invention. Hence, these descriptions and drawingsshould not be considered in a limiting sense, as it is understood thatthe present invention is in no way limited only to the embodimentsillustrated.

1. A system for radio frequency identification of a tag in aninterrogation zone, comprising: a calibration node disposed in theinterrogation zone to measure a signal strength of radio frequencyidentification signals from a beamforming system and provide signal datain accordance with the signal strength; and a reader node configured toreceive the signal data and adjust the radio frequency identificationsignals generated by the beamforming system based upon the signal data,wherein at least one of the calibration node, the reader node and thebeamforming system is a configurable monitoring system.
 2. The system ofclaim 1, wherein the calibration node, the reader node, and thebeamforming system are coupled in a feedback control loop.
 3. The systemof claim 2, wherein the beamforming system further comprises a pluralityof beamforming nodes.
 4. The system of claim 3, wherein a signal of atleast one beamforming node is optimized in accordance with the feedbackcontrol loop.
 5. The system of claim 3, wherein a signal to noise ratioof at least one beamforming node is optimized in accordance with thefeedback control loop.
 6. The system of claim 3, wherein a phase of atleast one beamforming node is optimized in accordance with the feedbackcontrol loop.
 7. The system of claim 3, wherein the plurality ofbeamforming nodes form a one dimensional beamforming array.
 8. Thesystem of claim 3, wherein the plurality of beamforming nodes form a twodimensional beamforming array.
 9. The system of claim 1, including aplurality of tags arranged in a mesh with tag to tag communicationbetween at least two of the tags in the mesh.
 10. The system of claim 9,wherein a tag within the interrogation zone is localized in accordancewith range data based on the tag to tag communication.
 11. The system ofclaim 9, wherein a tag within the interrogation zone is localized inaccordance with a combination of the signal data and range data based onthe tag to tag communication.
 12. The system of claim 9, wherein a tagwithin the interrogation zone is localized in accordance with the signaldata and a beacon signal provided within the interrogation zone.
 13. Thesystem of claim 12, wherein the beacon signal has multiple ranges forproviding multiple range determinations to localize the tag byperforming a logical operation on the multiple range determinations. 14.The system of claim 12, wherein the beacon signal is provided by aconfigurable monitoring device configured as a beacon.
 15. The system ofclaim 9, wherein the signal data is transmitted to the reader node byway of the tag to tag communication.
 16. The system of claim 9, whereinthe signal data is transmitted to the reader node by way of networkactivity nodes.
 17. The system of claim 9, wherein the signal data istransmitted to the reader node by way of a gateway node.
 18. The systemof claim 1, wherein the beamformer system receives the signal data andadjusts the radio frequency identification signals based on the signaldata.
 19. The system of claim 18, wherein the beamformer system receivesthe signal data by way of a control radio frequency connection.
 20. Thesystem of claim 18, wherein the beamformer system receives the signaldata by way of a hardwired connection.